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Question 14 Marks
The kinetic energy of an object is the energy associated with the object which is under motion. It is defined as "the energy required by a body to accelerate from rest to stated velocity." It is a vector quantity and the momentum of an object is the virtue of its mass. It is defined as the product of mass and velocity. It is a vector quantity. The relation between them is given by $E =\frac{P^2}{2 m}$. In case of the elastic collision both of these quantities remain constant.
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1.Two masses of 1 gm and 4 gm are moving with equal linear momentum. The ratio of their kinetic energy is:
(a) $1: 2$ (b) $4: 1$ (c) $1: 1$ (d) $4: 2$
2. If the linear momentum is increased by $50 \%$, then K .E will be increased by:
(a) $50 \%$ (b) $200 \%$ (c) $125 \%$ (d) $100 \%$
3.A heavy object and a light object have the same momentum. Which has the greater speed?
(a) both heavy and light object
(b) heavy object
(c) Moderate object
(d) light object
OR
Kinetic energy with any reference must be $\qquad$
(a) Change (b) negative (c) zero (d) positive
4.When a body moves with a constant speed along a circle then
(a) no acceleration is produced
(b) no work is done on it
(c) no displacement on it
(d) no force acts on it
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Question 24 Marks
Gas molecules move in random motion inside the container. The pressure exerted by the gas is due to the continuous collision of the molecules against the walls of the container. Due to this continuous collision, the walls experience a continuous force which is equal to the total momentum imparted to the walls per second.
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1. If the mass of each molecule is halved and speed is doubled, find the ratio of initial and final pressure:
(a) $1: 16$ (b) $1: 4$ (c) $1: 8$ (d) $1: 2$
2. The pressure exerted by the gases is:
(a) inversely proportional to the density
(b) inversely proportional to the square of the density
(c) directly proportional to the density
(d) directly proportional to the square of the density
3. If the force of attraction between the molecules suddenly disappears, then what will be the change in pressure:
(a) pressure increase
(b) pressure decrease
(c) pressure remains constant
(d) pressure falls
4. If the pressure of a given gas is halved at a certain temperature. what will be its volume:
(a) becomes triple (b) becomes double (c) remains constant (d) becomes half
OR
Dimension formula for R ?
(a) $M ^1 L^2 T^2 K^{-1}$ (b) $M ^1 L^1 T^{-1}$
(c) $M ^{-1} L^0 T^1$ (d) $M ^1 L^2 T^{-2} K^{-1}$
Answer
1. (d) $1: 2$
Explanation: 1:2
2. (c) directly proportional to the density
Explanation: directly proportional to the density
3. (a) pressure increase
Explanation: pressure increase
4. (b) becomes double
Explanation: becomes double
OR
(d) $M ^1 L^2 T^{-2} K^{-1}$
Explanation: $M ^1 L^2 T^{-2} K^{-1}$
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4 Marks Question - Physics STD 11 Science Questions - Vidyadip