Tag: physics

Questions Related to physics

Electromagnets are used in

physics applications of electromagnets

  1. electric bells only

  2. telephones only

  3. dynamos only

  4. all the above

Show answer
Correct Option: D
Explanation:

An electromagnet is a soft metal core made into a magnet by the passage of electric current through a coil surrounding it. It has a number of applications including electric bells, in telephones and in dynamos.

Electromagnets are used in

physics applications of electromagnets

  1. electric bells only.

  2. telephones only.

  3. dynamos only.

  4. all the above.

Show answer
Correct Option: D

In which of the following devices is an electromagnet used?
a. Electric tram
b. Loud speaker
c. Telegraph
d. Relay microphone

physics applications of electromagnets

  1. a

  2. b, c and d

  3. a and b

  4. All of the above

Show answer
Correct Option: D
Explanation:

An electromagnet is a temporary strong magnet made from a piece of soft iron when current flows in the coil wound around it. It is an artificial magnet and loses its magnetism when the current is removed. It is used in electric trams, loud speakers, telegraph, relay microphone etc to enhance the effect.

Match the following

1. Industrial use a. Study of magnetic properties under magnetic field
2. Scientific use b. Removing pieces of iron from wounds
3. Medical use c. To separate iron filaments from other waster
4. Easiest method d. Lifting and transporting heavy loads of iron mass
physics applications of electromagnets

  1. $1-d, 2-a, 3-b, 4-c$

  2. $1-b, 2-d, 3-c, 4-a$

  3. $1-c, 2-b, 3-a, 4-d$

  4. $1-a, 2-c, 3-d, 4-b$

Show answer
Correct Option: A
Explanation:

Electromagnets are used for various industrial, scientific, medical purposes mentioned above.

When the current through the electromagnet of a relay reaches a particular value.

physics applications of electromagnets

  1. It breaks the circuit

  2. It opens the circuit by pulling in an iron contact

  3. It closes the circuit by pulling in an iron contact

  4. Both A or C

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Correct Option: D

Two bodies A and B are said to be in thermal equilibrium with each other, if :

physics heat and energy zeroth law of thermodynamics

  1. heat flows from A to B

  2. heat flows from B to A

  3. both the bodies lose equal amounts of heat to the atmosphere

  4. heat does not flow from either A or B

Show answer
Correct Option: D
Explanation:

The correct answer is option(D).

Thermal equivalence happens when there is no temperature difference between two bodies. And no heat transfer happens.

For 2 gases in thermal equilibrium with each other , Pressure of the gases 

physics heat and energy zeroth law of thermodynamics

  1. varies as speed of the gas molecules

  2. varies as square root of the gas molecules

  3. varies inversely as the gas molecules

  4. remains same

Show answer
Correct Option: D
Explanation:

For the ideal gas equation $PV=nRT$

if T is constant the pressure is also constant
hence  when the gases in thermal equilibrium have same temperature their pressure remains same .
 hence option D is correct.

Two systems are in thermal equilibrium. The quantity which is common for them is

physics heat and energy zeroth law of thermodynamics

  1. heat

  2. momentum

  3. specific heat

  4. temperature

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Correct Option: D
Explanation:

Thermal equilibrium implies that there is no heat transfer taking place between the given two bodies i.e. there temperature is same.

When a gas  is in thermal equilibrium, its molecules

physics heat and energy zeroth law of thermodynamics

  1. have the same average kinetic energy.

  2. have different energies which remains constant.

  3. have a certain constant energy.

  4. do not collide with one another.

Show answer
Correct Option: A
Explanation:

When a gas is in thermal equilibrium, the temperature throughout the gas is the same. (Zeroth law of thermodynamics)
The average kinetic energy of the gas molecules is directly proportional to the absolute temperature of the gas. I.e. different sections of the gas will all have the same average kinetic energy.

Two metal spheres of different radii having same temperature are placed in thermal contact in a vaccum. Which of the following quantities is certainly correct?

physics heat and energy zeroth law of thermodynamics

  1. Each sphere has the same internal energy

  2. There is no net transfer of thermal energy between the spheres

  3. Both spheres radiate electromagnetic energy at the same rate

  4. The larger sphere a greater mean internal energy per atom than the smaller sphere

Show answer
Correct Option: B
Explanation:

There is no net transfer of thermal energy between the spheres.

Option B is correct.