WBBSE Solutions For Class 10 Physical Science And Environment Chapter 4 Thermal Phenomena

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WBBSE Class 10 Physical Science Solutions

Chapter 4 Thermal Phenomena MCQs

Question 1. What is the S.I. unit of Heat?

  1. Joule
  2. Calorie
  3. Kelvin
  4. Celsius

Answer: 1. Joule

Question 2. Two spheres made of material have radii in the ratio of 1: 2. Both are at the same temperature. The ratio of heat radiation energy emitted per second by them is :

  1. 1:2
  2. 1:8
  3. 1:4
  4. 1:16

Answer: 2. 1:4.

Question 3. The total number of divisions present in the fundamental interval of the Celsius scale is :

  1. 80
  2. 180
  3. 100
  4. 120

Answer: 3. 100.

Read And Learn More: WBBSE Solutions For Class 10 Physical Science And Environment

Question 4. 1 Calorie is equal to :

  1. 4.2J
  2. 4.2 erg.
  3. 1J
  4. 1.8 k

Answer: 1. 4.2J

Physics Class 10 WBBSE

Question 5. The rate of cooling at 600 K, if the surrounding temperature is 300k is R, The rate of cooling at 900 K is :

  1. \(\frac{16}{3} R\)
  2. 2R
  3. 3R
  4. \(\frac{2}{3} R\)

Answer: 1. R.

Question 6. If Im denotes the wavelength at which the radiative emission from a black body at a temperature TK is maximum, then

  1. λm α T
  2. λm α T2
  3. λm does not depend on T
  4. λm α T-1

Answer: 4. λm α T-1

Question 7. A body cools from 50°C to 40°C in 5 minutes. Its temperature comes down to 33.33°C in the next 5 minutes. The temperature of the surroundings is :

  1. 15°C
  2. 20°C
  3. 25°C
  4. 10°C

Answer: 2. 20°C.

Physics Class 10 WBBSE

Question 8. The volume of water is minimum at :

  1. 4°C
  2. 10°C
  3. 5°C
  4. 9°C

Answer: 1. 4°C.

Question 9. The density of water is maximum at :

  1. 40°C
  2. 4°C
  3. 10°C
  4. 25°C

Answer: 2. 4°C.

Question 10. The coefficient of linear expansion of a solid depends on :

  1. Unit of length
  2. Scale of temperature
  3. Density of the material
  4. None of these

Answer: 2. Scale of temperature.

Question11. A good insulator of heat is:

  1. Copper
  2. Mercury
  3. Trapped air
  4. Iron

Answer: 3. Trapped air.

Question 12. A body cools from 60°C to 50°C in 10 min. If the room temperature is 25°C, the temperature of the body at the end of the next 10 min. will be :

  1. 38.5°C
  2. 40°C
  3. 45°C
  4. 42.85°C

Answer: 4. 42.85°C.

Physics Class 10 WBBSE

Question 13. A black body has a maximum wavelength Im at 2000K. Its corresponding wavelength at 3000K will be :

  1. \(\frac{3}{2} \lambda \mathrm{m}\)
  2. \(\frac{2}{3} \lambda \mathrm{m}\)
  3. \(\frac{16}{81} \lambda \mathrm{m}\)
  4. \(\frac{81}{16} \lambda \mathrm{m}\)

Answer: 2. \(\frac{2}{3} \lambda \mathrm{m}\)

Question 14. If the temperature of a block body is doubled, the wavelength at which the spectral radiancy has its maximum is :

  1. Doubled
  2. Halved
  3. Quadrapled
  4. Unchanged

Answer: 2. Halved.

Question 15. A body takes T minutes is cool from 62°C to 61°C when the surrounding temperature is 30°C. The time taken by the body to cool is 30°C. The time taken by the body to cool 46°C to 45°C is:

  1. Greater than T minute
  2. Equal to T minute
  3. Equal to \(\frac{T}{2}\)
  4. Less than T minute

Answer: 1. Greater than T minute.

Question 16. Heat given to a body which rises its temperature by 1°C is :

  1. Water equivalent
  2. Specific heat
  3. Temperature gradient
  4. Thermal capacity

Answer: 4. Thermal capacity.

Question 17. During the adiabatic process, the pressure of a gas is found to be proportional to the cube of its absolute temperature.

The ratio \(\frac{C P}{C V}\) for gas is.

  1. \(\frac{4}{3}\)
  2. 2
  3. \(\frac{5}{3}\)
  4. \(\frac{3}{2}\)

Answer: 4. \(\frac{3}{2}\)

Physics Class 10 WBBSE

Question 18. Two bars of copper having the same length but unequal cross-section are heated to the same temperature. The change in length will be :

  1. Equal in both bars
  2. More in thinner bar
  3. More in thicker bar
  4. Cannot say

Answer: 1. Equal in both bars.

Question 19. A gaseous mixture consists of 16g of Helium and 16g of Oxygen. The ratio \(\) of the mixture is :

  1. 1.54
  2. 1.4
  3. 1.63
  4. 1.59

Answer: 3. 1.63.

Question 20. The specific heat of a gas in a gas in an isothermal process is:

  1. Infinite
  2. Zero
  3. Negative
  4. Remains zero

Answer: 1. Infinite.

WBBSE Class 10 Physical Science Question Answer

Question 21. What is the upper fixed point in the Fahrenheit scale?

  1. 212°F
  2. 232°F
  3. 202°F
  4. 211°F

Answer: 1. 212°F.

Question 22. The Fahrenheit and Kelvin scales of temperature will have the same reading at :

  1. – 40
  2. 313
  3. 574.25
  4. 732.25

Answer: 1. – 40.

Question 23. At what temperature, the volume of an ideal gas at 0°C becomes triple?

  1. 182°C
  2. 819°C
  3. 546°C
  4. 646°C

Answer: 3. 546°C.

Question 24. The specific heat of ice at 0°C melting into at 0°C is :

  1. Zero
  2. Infinity
  3. More than zero
  4. Less than zero

Answer: 2. Infinity.

Question 25. Boiling water is changing into steam. The specific heat of boiling water is :

  1. Zero
  2. One
  3. Infinity
  4. Less than one
  5. Answer: 3. Infinity.

WBBSE Class 10 Physical Science Question Answer

Question 26. Which of the following has the highest specific heat?

  1. Copper
  2. Water
  3. Hydrogen
  4. Silver

Answer: 3. Hydrogen.

Question 27. One gram of ice at 0°C is added at 5g of water to 10°C. The final temperature of the mixture is

  1. -5°C
  2. 5°C
  3. 0°C
  4. None of these

Answer: 1. – 5°C.

Question 28. The specific heat of an ideal gas varies with temperature T as:

  1. T1
  2. T2
  3. T-1
  4. T0

Answer: 4. T0 .

Question 29. 22g CO2, at 27°C is mixed with 16g of Oxygen at 37°C. The temperature of the mixture is:

  1. 32°C
  2. 27°C
  3. 37°C
  4. 30°C

Answer: 1. 32°C.

Question 30. A balloon contains 500 m3 of He at 27°C and 1 atmosphere pressure. The volume of He at -3°C and 0.5 atmosphere pressure will be :

  1. 70m3
  2. 900m3
  3. 1000m3
  4. 500m3

Answer: 2. 900 m3.

WBBSE Class 10 Physical Science Question Answer

Question 31. 100g of ice is mixed with 100g of water at 100°C. The final temperature of the mixture is :

  1. 10°C
  2. 20°C
  3. 40°C
  4. 30°C

Answer: 1. 10°C.

Question 32. For making a thermometer quick-acting.

  • The bulb of the thermometer should be of greater volume
  • The bulb of the thermometer should be of less volume
  • The bulb of the thermometer should be spherical

Answer: 2. Bulb of the thermometer should be of less volume

Question 33. The water equivalent of a body is 10 kg. Its thermal capacity is :

  1. 10JK-1
  2. 1JK-1
  3. 42000J.K-1

Answer: 3. 42000 J.K-1

Question 34. The liquid whose specific heat is the highest is :

  1. Water
  2. Alcohol
  3. Kerosene

Answer: 1. Water.

Question 35. Thermal capacity of 10g. a liquid having specific heat 0.03 in the CGS system is :

  1. 3cal.°C-1
  2. 30Cal.°C-1
  3. 33.3 Cal.°C-1
  4. 30 kelvin

Answer: 1. 3 Cal. °C-1

Question 36. If the temperature of a body is increased by 36° in the Fahrenheit scale then this increase in Celsius scale will be :

  1. 20°
  2. 36°
  3. 64.8°
  4. 55.9°

Answer: 1. 20°.

WBBSE Class 10 Physical Science Solutions

Question 37. An equal amount of heat is given to two liquids A and B of equal mass. The specific heat of B is twice that of A. The ratio of the rise in temperature of A and B will be :

  1. 1:1
  2. 1:2
  3. 2:3
  4. 2:1

Answer: 4. 2:1.

Question 38. 1°C change = _______ °F Change

  1. \(\frac{9}{6}\)
  2. \(\frac{9}{5}\)
  3. \(\frac{5}{9}\)
  4. \(\frac{16}{9}\)

Answer: 2. \(\frac{9}{5}\)

Question 39. The thermal capacity of a unit mass of a body is called its :

  1. Specific heat
  2. Mass
  3. Material temperature

Answer: 1. Specific heat.

Question 40. 0°C = ________ °F

  1. 32
  2. 40
  3. – 40
  4. -32

Answer: 1. 32.

WB Class 10 Physical Science Question Answer Chapter 4 Thermal Phenomena Very Short Answer Type Questions

Question 1. What is the fundamental principle of Calorimetry?
Answer: Heat lost by lost Heat gained by a cold body.

Question 2. What is the unit of coefficient of thermal conductivity in SI?
Answer: Wm K-1.

Question 3. Name the element which is the best conductor of heat.
Answer: Silver.

Question 4. What is the absorbing power of a perfectly black body?
Answer: One.

Question 5. What is the reflecting power of a perfectly black body?
Answer: Zero.

Question 6. What is an anomalous expansion of water?
Answer: In the range of 0°C to 4°C, the volume of water decreases instead of increasing, like other liquids. This is known as anomalous expansion of water.

Question 7. What is a perfectly black body?
Answer: A body which absorbs all radiations incident it.

Question 8. By which mode does the heat reach the earth from the Sun?
Answer: Radiation.

Question 9. Can convection take place in a solid?
Answer: No, for convection a fluid medium is required.

Question 10. What is the difference between 1°C and IC°?
Answer: 1°C is a particular temperature, while 1C° is the interval of one degree Celsius of temperature.

Question 11. Which is more expansible -solid, liquid or gas?
Answer: gas.

Question 12. Is the coefficient of linear expansion possible in the case of a liquid?
Answer: No, liquid has no definite length.

Question 13. What is the value of latent heat of fusion of ice in the CGS system?
Answer: 80 Calg-1.

Question 14. Is it possible that heat is supplied to a body without changing the temperature?
Answer: Yes, during a change of state there is no change in temperature although heat is supplied.

WB Class 10 Physical Science Question Answer

Question 15. Is there any upper fixed point in the Kelvin Scale?
Answer: 273.13K, which is the triple point of water.

Question 16. What is the reading of 27°C on the absolute scale?
Answer: The reading of the temperature in the absolute scale (273 + 27) 300K

Question 17. Which liquid has the highest specific heat?
Answer: The specific heat of water is the highest.

Question 18. Of 0°C and 0°F which one is less?
Answer: Of 0°C and 0°F, 0°F is less.

Question 19. How much work is to be performed to produce 1 cal heat?
Answer: To produce 1 cal heat, 4.2 × 107 erg or 4.2J work is to be performed.

Question 20. Of a liquid and a solid, whose specific heat is greater?
Answer: Usually specific heat of solids is less than that of liquids.

Physics Class 10 WBBSE Chapter 4 Thermal Phenomena Fill In The Blanks

Question 1. γr = γa  + ________.
Answer: γg

Question 2. The volume of water is minimum at _________.
Answer: 4°C.

Question 3. The density of water is maximum at __________.
Answer: 4°C.

Question 4. Carbon dioxide is a ________ gas.
Answer: Greenhouse.

WB Class 10 Physical Science Question Answer

Question 5. The unit of thermal conductivity in the CGS system is _________.
Answer: Cm2S-1.

Question 6. From Charle’s law, we find y = _________°C-1
Answer: \(\frac{1}{273}\)

Question 7. From pressure law, we find γv = _________ °C-1
Answer: \(\frac{1}{273}\)

Question 8. The specific heat of the water in the SI system is
Answer: 4200 J Kg-1 K-1.

Question 9. The unit of thermal conductivity in the SI system is _________.
Answer: Jm-1 S-1 K-1

Question 10. 1 calorie = ________ Jule.
Answer: 4.18

Question 11. Heat is a form of _________.
Answer: Energy.

Question 12. Three different types of motions are translational motion, vibrational motion and _________.
Answer: Rotational motion.

Question 13. SI unit of heat is _________.
Answer: Joule.

Question 14. Temperatures are measured with a __________.
Answer: Thermometer.

Question 15. _________ is the upper fixed point in the Fahrenheit scale.
Answer: 212° F

Question 16. Three types of expansions in solids are linear expansion, superficial expansion and _________.
Answer: Volume expansion

Question 17. Real expansion of the liquid = expansion of the vessel + _________.
Answer: Apparent expansion of the liquid.

Question 18. The specific heat of a gas in an isothermal process is :
Answer: Infinite

Question 19. The specific heat of an ideal gas varies with temperature T as ___________.
Answer: T0

Question 20. 100g of ice is mixed with 100g of water at 100°C. The final temperature of the mixture is __________.
Answer: 10°C.

Question 21. Wax _______ definite melting point.
Answer: Has no.

Question 22. The unit of latent heat in SI is
Answer: J.Kg-1

Question 23. A mixture of ice and common salt is known as ________.
Answer: Freezing mixture.

Question 24. With the increase of pressure boiling point of water _______.
Answer: Increases.

Question 25. The amount of heat required to convert 2g of water at 100°C completely into steam at the same temperature is ________.
Answer: 200 cal.

Question 26. If the air contains more water vapour then rate of evaporation _________.
Answer: Decreases.

Question 27. If 80 cal of heat is given to lg of ice at 0°C, its temperature will be
Answer: 0°C.

Question 28. _______ has the highest specific heat.
Answer: Hydrogen

Question 29. 100g. of ice is mixed with 100g of water at 100°C. The final temperature of the mixture is _______.
Answer: 10°C

Question 30. ________ is the best conductor of heat.
Answer: Silver.

Class 10 Physical Science Solution WBBSE Chapter 4 Thermal Phenomena Short Answer Type Questions

Question 1. What do you mean by heat?
Answer:

Heat: It is a form of energy which produces a sensation of warmth.

Question 2. What are the different types of solutions?
Answer:

Different types of motions are

  1. Translational motion
  2. Vibrational motion
  3. Rotational motion

Question 3. What is the definition of heat with respect to motion?
Answer:

Definition of heat with respect to motion:

Heat possessed by a body is the total thermal energy of the body and is the sum of kinetic energies of all the individual molecules forming the body due to translational, vibrational and rotational to translational, vibrational and rotational motions of molecules.

Question 4. What is temperature?
Answer:

Temperature: It is the thermal condition of a body that determines the direction of flow of heat when the body is placed in thermal contact with another body.

Question 5. What do you mean by calorie?
Answer:

Calorie

Calorie It is the quantity of heat required to raise the temperature of 1 g water through 1°C.

Question 6. What is the upper fixed point of a thermometer?
Answer:

Upper fixed point: It is the temperature of steam from water boiling under a pressure of 86cm. of mercury at sea pressure of 76 cm. of mercury at sea level and 45° latitude.

Question 7. What is the water equivalent of a body?
Answer:

Water equivalent: The water equivalent of a body is the mass of water that will be heated through one degree by the amount of heat that raises the temperature of the body through one degree.

WBBSE Solutions Guide Class 10

Question 8. What is molar-specific heat at constant pressure? (CP)?
Answer:

Molar-specific heat at constant pressure:

The molar specific heat of a gas at constant pressure (CP) is the amount of heat required to raise the heat required to raise the temperature of one mole of the gas through one degree keeping the pressure constant throughout.

Question 9. What is the lower fixed point of a thermometer?
Answer:

Lower fixed point: It is the temperature of melting ice under a pressure of 16 cm of mercury at sea level and 45° latitude.

Question 10. What is a fundamental interval?
Answer:

Fundamental Interval: The difference between the fixed point of a scale is called a fundamental interval.

Question 11. What do you mean by thermal expansion?
Answer:

Thermal Expansion: The dimension of all substances generally increases with an increase in temperature. The phenomenon is known as thermal expansion.

Question 12. What are the types of expansion in solids?
Answer:

Types of expansions in solid :

  • Linear expansions
  • Superficial expansions
  • Volume expansions.

Question 13. What is an apparent expansion of the liquid?
Answer:

Apparent expansion of the liquid: If the expansion of the liquid is measured ignoring the expansion is called the apparent expansion of the liquid.

Question 14. What is the real expansion of the liquid?
Answer:

Real expansion of the liquid: When the actual expansion of the liquid is measured by considering the expansion of the containing vessel, it is called real expansion of the liquid.

Question 15. What is the conclusion of Hope’s experiment?
Answer:

Conclusion of Hope’s experiment:

From Hope’s experiment, it is proved that water at the bottom is densest at 4°C. After a sufficiently long time, the temperature of the lower thermometer falls slightly due to loss of heat by conduction to the upper regions.

WBBSE Solutions Guide Class 10

Question 16. What is molar-specific heat at constant volume (CV)?
Answer:

Molar specific heat at constant volume (Cv): The molar specific heat of a gas at constant volume (Cv) is the amount of heat required to raise the temperature of one mole of the gas through one degree keeping the volume constant throughout.

Question 17. What is Regelation?
Answer:

Regelation: The phenomenon of melting of ice under pressure and freezing again on releasing the pressure is called regelation.

Question 18. What do you mean by the vapour pressure of a liquid?
Answer:

Vapour pressure: Whenever a liquid evaporates at any temperature, the vapour exerts a definite pressure on everything in contact. This pressure is called the vapour pressure of the liquid a that temperature.

Question 19. What is the conduction of heat?
Answer:

Conduction: It is the process of the transfer of heat through a substance without any detectable motion of the particles of the substance.

Question 20. What is the Radiation of heat?
Answer:

Radiation: It is the transmission of heat from a hot body to a cold body without the help of any medium and without appreciable heating at the intervening medium if any.

Question 21. What is the perfectly black body?
Answer:

Perfectly black body: A perfectly black body is that which absorbs completely the radiations of all the wavelengths on it.

Question 22. What is the greenhouse effect?
Answer:

Greenhouse effect: The greenhouse effect is an example of the selective absorption of heat by glass. The amount of heat transmitted through a substance depends on the temperature of the source of heat.

WBBSE Solutions Guide Class 10

Question 23. What is the convection of heat?
Answer:

Convection of heat: It is the process by which heat is transmitted through a liquid or gas from a hotter point to a colder point due to the bodily motion of the heated particles of the substances.

Question 24. What do you mean by global warming?
Answer:

Global warming: Carbon dioxide, water vapour, methane, nitrous oxide, tropospheric ozone, chloro-fluoro carbon compounds, halogens compounds etc. Increasing the amount of greenhouse gases in the atmosphere, the temperature of earth increases, It is known as global warming.

Question 25. What is the thermal expansion of solids?
Answer:

Thermal expansion of solids

The dimensions of all substances increase with the increase in temperature. The phenomenon is known as the thermal expansion of solids.

Question 26. Define the coefficient of linear expansion of a solid.
Answer:

The coefficient of linear expansion of a solid

The coefficient of linear expansion is defined as the fractional increase in the length of the solid per degree rise in temperature.

Question 27. How do you relate the coefficient of linear expansion of a rod with the length and temperature?
Answer:

The increase in the length of the rod due to heating is very nearly proportional to the length of the rod and the rise in temperature.

Class 10 Physical Science WBBSE

Question 28. Define the coefficient of superficial Expansion.
Answer:

The coefficient of superficial Expansion

The coefficient of superficial expansion of a solid is defined as the fractional change in its temperature.

Question 29. Define the coefficient of cubical expansion of a solid.
Answer:

The coefficient of cubical expansion of a solid is defined as the fractional increase in the volume of the solid per degree rise in temperature.

Question 30. A brass disc fits tightly into the base of the steel plate. Should you apply heat in order to remove the disc from the base?
Answer:

  • The coefficient of linear expansion of brass is greater than that of steel. So if we apply heat then the brass disc will fit more tightly into the base. But it we cool the concerned region.
  • Then the decrease in the diameter of the brass disc will be more than that of the base of the steel plate. So the disc will become loose and can be easily removed from the bore.

Question 31. Define the apparent thermal expansion of liquids.
Answer:

When the expansion is measured by ignoring the expansion of the containing vessel it is called the apparent expansion of the liquid.

Question 32. What do you mean by the coefficient of real expansion of liquid?
Answer:

Coefficient of real expansion of liquid

The coefficient of real expansion of liquid is the fraction of its volume by which it actually expands at are degree rise in temperature.

Question 33. Write the relation between the expansion coefficient of liquid. Yr = Ya + Yg.
Answer:

Relation between the expansion coefficient of liquid. Yr = Ya + Yg

Yr = Coefficient of real expansion of a liquid

Ya = Coefficient of apparent expansion of liquid

Yg = coefficient of volume expansion of the material of the vessel.

Class 10 Physical Science WBBSE

Question 34. What is a weight thermometer?
Answer:

Weight thermometer

The coefficient of apparent expansion of a liquid may be determined with a thermometer, it is called a weight thermometer.

Question 35. Power Supply lines or telephone lines are slightly sagged, why?
Answer:

Power Supply lines or telephone lines are slightly sagged,

The lines contract being cooled in winter. If they are kept taught before two plates, then due to the thermal stress. Lives may tumble or the lines may srap.

Question 36. A breaker is filled to the brain with water at 4°C. What will you notice if the temperature is decreased or increased? Give reasons for your answer.
Answer:

A breaker is filled to the brain with water at 4°C

The density of water is greatest at 4°C, and the volume of a given mass of water is least at that temperature. As the bear was filled to the brim, in both cases, the wafer overflowed from the beaker.

Question 37. The state of a fixed mass of a gas at constant temperature is inversely proportional to its pressure.
Answer:

\(V \alpha \frac{1}{p}\)

Question 38. Write the relation between the pressure and density of a gas at a constant pressure.
Answer:

The density of a gas at a constant temperature is proportional to pressure \(\frac{p}{\ell}\) = constant (P = pressure p = pressure)

Question 39. State Charles’ law.Question
Answer:

Charles’ law

The pressure remaining constant, the volume of a given mass of any gas increases or decreases by the constant fraction \(\frac{1}{273}\) of its volume at 0°C, for every degree Celsius increases or decreases of temperature.

Question 40. Define the volume coefficient of a gas.
Answer:

The volume coefficient of a gas

The volume coefficient (yp) of a gas may be defined as the fractional increase in the volume of the gas at 0°C for each degree Celsius rise in temperature, the pressure being kept constant.

 

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