Tag: physics

Questions Related to physics

True & False Statement Type
$S _1$ : In an elastic collision initial and final K.E. of system will be same.
$S _2$ : In a pure L-C Circuit average energy stored in capacitor is zero.
$S _3$ : In YDSE coherent sources are formed by division of wave front method.
$S _4$ : If a physical Quantity is quantized then it must be integral multiple of its lowest value.

physics superposition of waves coherence young's double slit experiment interference

  1. FFTF

  2. TTFT

  3. FTFT

  4. TFTT

Show answer
Correct Option: D
Explanation:

S1: In an elastic collision the kinetic energy is conserved so the initial and final K.E. of system will be same. (T)
S2: In a pure L-C Circuit average energy stored in capacitor always oscillate between a maximum and a minimum. So not zero always.(F)
S3:In YDSE coherent sources are formed by division of wavefront method from a single source of light. (T)
S4: If a physical Quantity is quantized then it will be the integral multiple of its lowest value (T)

State whether the given statement is True or False
The boiling point of liquid increases with increase in pressure.

physics the kinetic model of matter evaporation heat, internal energy and work phase change

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

The rate of evaporation  increase with a decrease in the gas pressure around a liquid. Molecules like to move from areas of higher pressure to lower pressure

Rate of evaporation increases 

physics the kinetic model of matter evaporation heat, internal energy and work phase change

  1. with the rise in temperature

  2. with the fall in temperature

  3. irrespective of temperature

  4. only beyond room temperature

Show answer
Correct Option: A
Explanation:

Rate of evaporation Increases with the rise in temperature as increasing temperature increases the kinetic energy of molecules of the liquid which facilitates the molecule to convert into vapour.

Water evaporates under atmospheric pressure. Without changing the temperature, the same water is placed under partial vacuum. The rate of evaporation _________.

physics the kinetic model of matter evaporation heat, internal energy and work phase change

  1. increases

  2. drop to zero

  3. decreases

  4. remain unaffected

Show answer
Correct Option: A
Explanation:
In partial pressure, the pressure is less;
According to Le-chatlier's principle on decreasing pressure; volume increases, so more water into gas(vapour)
So, rate of evaporation increases.

When the temperature of water rises, the rate of evaporation

physics the kinetic model of matter evaporation heat, internal energy and work phase change

  1. increases

  2. decreases

  3. remain the same

  4. first decrease then increases

Show answer
Correct Option: A
Explanation:

The higher the temperature of the substance the greater the kinetic energy of the molecules at its surface and therefore the faster the rate of their evaporation.

One of the most common phenomenon related to rainfall is

physics the kinetic model of matter evaporation heat, internal energy and work phase change

  1. Evaporation

  2. Vaporization

  3. Fusion

  4. Solidification

Show answer
Correct Option: A
Explanation:

Rainfall occurs primarily due to evaporation of water from water bodies like lakes and oceans and condensation of water in the form of precipitation like rainfall or snowfall.

From the following which are the factors affecting the rate of evaporation?

physics the kinetic model of matter evaporation heat, internal energy and work phase change

  1. Temperature

  2. Humidity

  3. Exposed Surface Area

  4. All of the above

Show answer
Correct Option: D
Explanation:

1. Temperature - If we increase the temperature of a liquid, its molecules get more kinetic energy and more molecules will come out rapidly from the surface of liquid i.e. rate of evaporation increases.


2. Humidity - Humidity is measurement of amount of vapour present in air. If humidity is high, it will be difficult for liquid to add more vapour in air as there is already high amount of vapour, therefore with increase in humidity, rate of evaporation decreases and vice- versa.


3. Exposed surface area - If exposed surface area is increased, more liquid molecules come on the surface, as evaporation is a surface process, therefore rate of evaporation increases.

Hence, all these factors affect the rate of evaporation.

Evaporation is which type of process

physics the kinetic model of matter evaporation heat, internal energy and work phase change

  1. Rapid

  2. Slow

  3. medium

  4. Neutral

Show answer
Correct Option: B
Explanation:

Evaporation and boiling, both are vaporisation. Boiling is a rapid process, which happens in the whole liquid whereas evaporation happens only on the surface of liquid and is a slow process.

State True or False :
The larger the exposed surface area, lower is the rate of evaporation.

physics the kinetic model of matter evaporation heat, internal energy and work phase change

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Larger surface area means more molecules per unit volume in the exposed surface area , which are capable to go out from surface i.e. larger rate of evaporation . Hence given statement is false .

State True and False :
If humidity is high in the atmosphere, rate of evaporation is higher. 

physics the kinetic model of matter evaporation heat, internal energy and work phase change

  1. True

  2. False

Show answer
Correct Option: B
Explanation:
If the humidity is high in the atmosphere, the rate of evaporation is lower as the air is full of water vapour and not able to take more of humidity. Thus, evaporation process becomes slower.