Heat

Q. A lead bullet strikes against a steel plate with a velocity $200m/s$. If the impact is perfectly inelastic and the heat produced is equally shared between the bullet and the target, then the rise in temperature (in ${}^{\circ }C$) of the bullet is (specific heat capacity of lead $s=125J/kgK$)

Q. Absolute zero temperature is not the temperature of zero energy why?

Q. Density of water with increasing temperature.

1. increases
2. decreases
3. remains unchanged

Q.

Define one calorie of heat.

Q.

Good absorbers are -____________ radiators.

Q. $C{O}_2(O-C-O)$is a triatomic gas. Mean kinetic energy of one-gram gas will be
(If $N$, Avogadro number; $k$, Boltzmann constant and molecular weight of $C{O}_2=44$)

1. $3/88NkT$
2. $6/88NkT$
3. $5/88NkT$
4. $7/88NkT$

Q. A metallic ball and highly stretched spring are made of the same material and have the same mass. They are heated so that they melt, the latent heat required_____

1. for the two may or may not be the same depending upon the metal.
   
2. is greater for the spring.
   
3. is greater for the ball.
   
4. are the same for both.
   

Q.

When heat is supplied to the matter, its molecules gain energy and start vibrating vigorously.

1. True
2. False

Q.

the density of sea water is

1. less than that of freshwater

2. greater than that of freshwater

3. equal to that of freshwater

4. may be greater than or less than that of freshwater

Q. Identify the pair of physical quantities which have different dimensions.

Q. The temperature of a solid object is observed to be constant during a period. In the period
(i) heat may have been supplied to the body.
(ii) heat may have been extracted from the body.
(iii) no heat is supplied to the body.
(iv) no heat is extracted from the body.

1. $\left(ii\right),\left(iii\right)$
2. $\left(i\right),\left(iv\right)$
3. 
   
   $\left(i\right),\left(iii\right)$
4. $\left(iii\right),\left(iv\right)$

Q.

What is heat capacity?

Q.

Hotter body transfer heat to a cooler body.

1. True
2. False

Q. Two particles of equal mass $m$ have respective initial velocities $u\hat{i}$ and $u\left(\frac{\hat{i}+\hat{j}}{2}\right)$They collide completely inelastically. The energy lost in the process is

1. $\frac{1}{8}m{u}^2$
2. $\frac{3}{4}m{u}^2$
3. $\sqrt{\frac{2}{3}}m{u}^2$
4. $\frac{1}{3}m{u}^2$

Q. A brass boiler has a base area of $0.15m^2$ and thickness $1.0\text{cm}$. It boils water at the rate of $6.0kg/min$⁡ when placed on a gas stove. Estimate the temperature of the part of the flame in contact with the boiler. Thermal conductivity of brass $=109J/smK;$ Heat of vaporisation of water $=2256\times {10}^{3}J/kg$.

Q.

What do you mean by specific heat?

Q. A rod $CD$ of thermal resistance $5.0{\text{KW}}^{-1}$ is joined at the middle of an identical rod $AB$ as shown in the figure. The ends $A,B$ and $D$ are maintained at ${100}^{\circ }\text{C}$, $0^{\circ }\text{C}$ and ${25}^{\circ }\text{C}$ respectively. Find the heat current in $CD$.

1. $2\text{W}$
2. $3\text{W}$
3. $4\text{W}$
4. $5\text{W}$

Q. Three copper blocks of masses $M_1,M_2,\text{and}{M}_{3}kg$ respectively are brought into thermal contact till they reach equilibrium. Before contact, they were at $T_1,T_2,T_3(T_1>T_2>T_3)$. Assuming there is no heat loss to the surroundings, the equilibrium temperature $T$ is (𝑠 is specific heat of copper)

1. $T=\frac{M_1{T}_{1}s+M_2{T}_{2}s+M_3{T}_{3}s}{M_1+M_2+M_3}$
2. $T=\frac{M_1{T}_1+M_2{T}_2+M_3{T}_3}{M_1+M_2+M_3}$
3. $T=\frac{M_1{T}_1+M_2{T}_2+M_3{T}_3}{3(M_1+M_2+M_3)}$
4. $T=\frac{T_1+T_2+T_3}{3}$
   

Q. At a certain instant a stationary transverse wave is found to have maximum kinetic energy. The appearance of string at that instant is

1. sinusoidal shape with amplitude $A/2$
2. sinusoidal shape with amplitude $A$
3. straight line
4. sinusoidal shape with amplitude $A/3$

Q.

Water has a maximum density at

1. $0^0\text{C}$
2. ${32}^0\text{F}$
3. $-4^0\text{C}$
4. $4^0\text{C}$

Q. A wooden spoon is dipped in a cup of ice cream. It's another end

1. Become cold by the process of conduction
2. Become cold by the process of convection
3. Become cold by the process of radiation
4. Does not become cold

Q. ntA Carnot engine, having an efficiency of as heat engine, is used as a refrigerator. If the work done on the system is 10J, the amount of energy absorbed from the reservoir at lower temperature isn nt1- 90Jn nt2- 1Jn nt3- 100Jn nt4- 99Jn

Q.

Salt water is denser than freshwater.

1. True
2. False

Q. The specific heat capacity of a body depends on:

1. the heat given
2. the temprature raised
3. the mass of the body
4. the material of the body

Q. Density of water with increasing temperature.

1. increases
2. decreases
3. remains unchanged

Q. Assertion :The flow of heat energy from one body to the other depends upon the amount of heat energy in them. Reason: Heat flows from lower temperature of the body to higher temperature of the body.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Assertion is incorrect but Reason is correct

Q. The absolute value of internal energy of a substance can be determined.If true enter 1 else 0.

1. 0

Q. Two identical rods of a mental are welded in series then 20 cal of heat flows through them in 4 minute. If the rods are welded in parallel then same amount of heat will flow in

1. 1 minute
2. 2 minute
3. 4 minute
4. 15 minute

Q.

If heat is due kinetic energy of molecules then why heat is not felt when molecules move when we on fan

Q. Find out the odd one from the given options.

1. $Calorie$
2. $Ampere$
3. $Joule$
4. $Kelvin$