Thermal Expansion

Q. cooling rate of a sphere of 600 K at external environment (200 K) is R. When the temperature of sphere is reduced to 400 K then cooling rate of the sphere becomes : (1) 3/16 R (2) 16/3 R (3) 9/27 R (4) None

Q.

The apparent coefficient of expansion of a liquid when heated in a copper vessel is C and when heated in a silver vessel is S. If A is the linear coefficient of expansion of copper, then the linear coefficient of expansion of silver is

1. 

2. 

3. 

4. 

Q.

Solids expand on heating because

1. Kinetic energy of the atoms increases

2. Potential energy of the atoms increases

3. Total energy of the atoms increases

4. The potential energy curve is asymmetric about the equilibrium distance between neighbouring atoms

Q. A bimetallic strip is formed out of two identical strips, one of copper and other of brass. The coefficients of linear expansion of the two metals are ${\alpha }_C$ and ${\alpha }_B$. On heating, the temperature of the strip goes up by $\Delta$T and the strip bends to form an arc of radius of curvature R. Then R is

1. Proportional to T
2. Inversely proportional to T
3. Proportional to
4. Inversely proportional to

Q. 8.The molar specific heat at constant pressure of an ideal gas is (7/2)R. The ratio of specific heat at constant pressure to that at constant volume is

Q.

The relation between the coefficients of linear expansion, α and volume expansion, γ is

1. γ = 3α

2. γ = α

3. γ = α3

4. γ = 3/α

Q.

A wall is made up of two layers A and B. The thickness of the two layers is the same, but materials are different. The thermal conductivity of A is double than that of B. In thermal equilibrium the temperature difference between the two ends of wall is ${36}^{o}C$. Then the difference of temperature at the two surfaces of A will be

1. 

2. 

3. 

4. 

Q.

A bar of iron is 10 cm at 20°C. At 19°C it will be (a of iron = 11 ´ 10^-6/°C)

1. 11 ´ 10^-5 cm longer

2. 11 ´ 10^-6 cm shorter

3. 11 ´ 10^-6 cm longer

4. 11 ´ 10^-5 cm shorter

Q. 16. A solid cylinder rolls down an inclined plane of height 3 m and reaches the bottom of plane with angular velocity of2\sqrt2 rad/s The radius of cylinder must be \lbrack Take g = 10ms2\rbrack

Q. a jar has mixture of hydrogen and oxygen gases in the ratio 1is to 5 ratio of mean kinetic energy of hydrogen and oxgen moleculei

Q.

An ice block is in a trough which is rotating about vertical axis passing through its centre. When ice melts completely, the angular velocity of the system

1. Increases

2. Decreases

3. Remains same

4. Becomes double

Q. A hole is drilled in a copper sheet. The diameter of the hole is $4.24\text{cm}$ at $27{}^{\circ }\text{C}$. Diameter of the hole when it is heated to $35{}^{\circ }\text{C}$ is

1. Less than $4.24\text{cm}$
2. Equal to $4.24\text{cm}$
3. More than $4.24\text{cm}$
4. Data insufficient

Q. For water at 0^° C it takes one hour for first 3 mmof ice layer formation. How much time will it takefor next 6 mm of ice formation?

Q. A compound pendulum has a time period T about a certain point in a vertical plane about a fixed axispassing through the pendulum. The maximum number of point on a vertical line passing throughcentre of mass about which time period will be T is(2) 4(3) 8(4) 6

Q. a gas filled in a cylinder its temperature is increased by 20% and volume is decreased by 20% if pressure remains cons†an t what percentage of mass of the gas leaks out

Q. 27.The maximum time period period of any simple pendulum on the earth is

Q. A wire of length 2m is made from $10c{m}^3$of copper. A force F is applied so that its length increases by 2 mm. Another wire of length 8 m is made from the same volume of copper. If the force F is applied to it, its length will increase by

1. 0.8 cm
2. 1.6 cm
3. 2.4 cm
4. 3.2 cm

Q.

A litre of alcohol weighs

1. Less in summer than in winter

2. Some both in summer and winter

3. Less in winter than in summer

4. None of the above

Q. A steel tape 1m long is correctly calibrated for a temperature of 27.0 °C. The length of a steel rod measured by this tape is found to be 63.0 cm on a hot day when the temperature is 45.0 °C. What is the actual length of the steel rod on that day ? What is the length of the same steel rod on a day when the temperature is 27.0 °C ? Coefficient of linear expansion of steel = 1.20 × 10¯⁵ K¯¹ .

Q. A seconds pendulum clock has a steel wire. The clock shows correct time at ${25}^{0}C$. How much time does the clock loose or gain, in one week, when the temperature is increased to ${35}^{0}C$?
($\alpha steel=1.2\times {10}^{-5}{/}^{0}C$)

1. 321.5 s
2. 3.828 s
3. 82.35 s
4. 36.28 s

Q. Two metal strips that constitute a thermostat must necessarily differ in their

1. Mass
2. Length
3. Resistivity
4. Coefficient of linear expansion

Q.

In variable state, the rate of flow of heat is controlled by

1. Density of material

2. Specific heat

3. Thermal conductivity

4. All the above factors

Q. An iron rod of length $50cm$ is joined at an end to an aluminium rod of length $100cm$. All measurements are made at ${20}^{\circ }C$. Find the length of the composite system at ${100}^{\circ }C$ and its average coefficient of linear expansion. The coefficient of linear expansion of iron and aluminium are $12\times {10}^{-6}{/}^{\circ }C$ and $24\times {10}^{-6}{/}^{\circ }C$ respectively.

1. 21 × 10^-6/°C

2. 20 × 10^-6/°C

3. 15 × 10^-5/°C

4. 18 × 10^-6/°C

Q. (3) 7425 L atm(4O28. An ideal gas is allowed to expand from 5 L to 15 L once rapidly and once very slowly. The magnitude of wor(a)done in two processes are W, and W, they are related as2(1) W, = W2(2) W, > W2C(3) W< W(4) Data is insufficient

Q.

A copper and a tungsten plate having a thickness $\delta$ = 2mm each are riveted together so that at $0^{\circ }C$ they form a flat bimetallic plate. Find the average radius of the curvature of this plate at $t$ = ${200}^{\circ }C$. The coefficient of linear expansion for copper and tungsten are ${\alpha }_{Cu}$ = $1.7\times {10}^{-5}/K$ and ${\alpha }_W$ = $0.4\times {10}^{-5}/K$.

1. 0.769 m

2. 1.243 m

3. 0.582 m

4. 1 m

Q. 3 moles of nitrogen and 2 moles of carbon dioxide are mixed in a container γ of the gaseous mixture is?

Q. a runner moves along the road at 2.0 m/s in still air that is at a temperature of 29 degree celcius.His surface area is 1.4 metre square, of which approximately 85% is exposed to air.Find the rate of converctive heat loss from his skin at a temperature 35 degree celcius to the outside air?Coefficient of convection for dry air and bare skin at wind speed 2.0m/s is 22W/metersquare degree celcius.

Q. ntTwo rods of same material have same length and area.The heat delta Q flows through them for 12 min when they are joined side by side.If now both the rods are joined in parallel then the amount of heat delta Q will flow inn nta)24 min b)3 min c)12 min d)6 minn

Q.

There is a rectangular metal plate in which two cavities in the shape of a rectangle and a circle are made, as show with dimensions. $P$ and $Q$ are centers of these cavities. On heating the plate, which of the following quantities increase?

1. $\pi r^2$

2. $ab$

3. $R$

4. $b$

Q. 14.4 moles of O3 gas dissociates 75% into O3 and 25% into O AT temp T .the change in internal energy is