Tag: physics

Questions Related to physics

Which of the following is an insulating component in thermos flask?

thermo flask thermos flask heat energy transfers transfer of heat physics

  1. plastic foam

  2. air

  3. vacuum

  4. All of the above

Show answer
Correct Option: D
Explanation:
Insulating component in thermos flask are plastic foam, air, vacuum.
As plastic foam is insulator, so to prevent heat to radiate plastic foam is used just after the inner layer, plastic foam is being polished to reflect the inner heat inside, as air is bad conductor of heat it does not conduct heat just outside the outer layer. Vacuum is poor conductor of heat. It is situated between two layers, which prevents heat conduction through convection.

The purpose of using vacuum flask is to store

thermo flask thermos flask heat energy transfers transfer of heat physics

  1. hot drinks.

  2. cold drinks.

  3. hot as well as cold drinks.

  4. None of these

Show answer
Correct Option: C
Explanation:
The purpose of using the vacuum flask is to store hot as well as cold drinks.
The basic concept behind using the vacuum flask is to keep the temperature of liquid constant which is being kept in the flask, no heat transfer would take place via conduction, convection or radiation.

A themoflask prevent heat loss from-

thermo flask thermos flask heat energy transfers transfer of heat physics

  1. Conduction

  2. Convection

  3. radiation

  4. all of these

Show answer
Correct Option: D
Explanation:
A thermoflask prevent heat loss from conduction, convection and radiation.
As it has insulator between two layers, it prevents the direct contact with surrounding and also stops the molecular motion for heat transfer. As it is a closed system surrounded by the layer of insulator, radiation can't even take place.

Study of internal structure of earth is known is

physics circular motion and gravitation elementary ideas of astronomy shadow formation and optical medium light and shadow

  1. Mechanics

  2. Nuclear physics

  3. Atomic physics

  4. Geophysics

Show answer
Correct Option: D
Explanation:

Study of internal structure of earth is known is $Geophysics.$

Hence,
option $(D)$ is correct answer.

A satellite of mass $m$ is revolving around the earth at height $R$ (radius of the earth) from the earth's surface. Its potential energy will be :

physics circular motion and gravitation elementary ideas of astronomy shadow formation and optical medium light and shadow

  1. $mgR$

  2. $0.67 mgR$

  3. $-\dfrac{mgR}{2}$

  4. $0.33mgR$

Show answer
Correct Option: A

what is mass of the moon?

physics gravitation elementary ideas of astronomy shadow formation and optical medium light and shadow

  1. $6 \times {10^{24}}$ kg

  2. $7.4 \times {10^{22}}$ kg

  3. $6 \times {10^{22}}$ kg

  4. $7.4 \times {10^{24}}$ kg

Show answer
Correct Option: B
Explanation:

The mass of the moon is $7.4\times 10^{22}kg.$

The correct option is B.

Lunar eclipse occurs when earth comes in between sun and the moon. Solar eclipse occurs when moon comes in between sun and earth. This suggests that:

physics light and shadow elementary ideas of astronomy shadow formation and optical medium the solar system nature and sources of light how light travels

  1. Both eclipses occur on a new moon day

  2. Solar eclipse occurs on a new moon day

  3. Lunar eclipse occurs on a new moon day

  4. Both eclipses occur on a full moon day

Show answer
Correct Option: B
Explanation:

A solar eclipse occurs when the Moon passes between the Sun and

Earth, and the Moon fully or partially blocks the Sun. This

can happen only at new moon, when the Sun and the Moon are in

conjunction as seen from Earth in an alignment.
A lunar eclipse occurs when the Moon passes

directly behind the Earth into its shadow. This can occur only

when the Sun, Earth, and Moon are aligned exactly, or very

closely so, with the Earth in the middle. Hence, a lunar eclipse can only occur the night of a full moon.

Lunar eclipse occurs when the

physics light and shadow elementary ideas of astronomy shadow formation and optical medium the solar system nature and sources of light how light travels

  1. Sun comes between the Earth and the Moon.

  2. Moon comes between the Earth and the Sun.

  3. Earth comes between the Moon and the Sun.

  4. the Earth and Moon collide with each other.

Show answer
Correct Option: C
Explanation:

The Moon moves around the Earth and the Earth moves around the Sun. During their revolutions, when the Moon, the Earth and the Sun come into a straight line keeping the Earth in between the Moon and the Sun, the lunar eclipse takes place.

The partial or complete hiding of one heavenly body by shadow of another is called

physics light and shadow elementary ideas of astronomy shadow formation and optical medium the solar system nature and sources of light how light travels

  1. Ellipse

  2. Eclipse

  3. Asteriod

  4. None of the above

Show answer
Correct Option: B
Explanation:

Eclipse is partial or complete hiding of one heavenly body by shadow of another.

Solar eclipse and lunar eclipse are two processes associated with earth, moon and sun.

Types of eclipses:

physics light and shadow elementary ideas of astronomy shadow formation and optical medium the solar system nature and sources of light how light travels

  1. only solar

  2. only lunar

  3. solar and lunar

  4. neither solar nor lunar

Show answer
Correct Option: C
Explanation:

There are 2 types of eclipses:
Solar
Lunar