Tag: internal energy

Questions Related to internal energy

When you heat the water in a pot, it boils. What do you infer from above observation?

physics heat energy transfers heat energy heat, internal energy and work internal energy

  1. Heat is a form of energy

  2. Water can boil itself

  3. Water develops heat on its own

  4. None of the above

Show answer
Correct Option: A
Explanation:

Boiling of water requires energy. Therefore heat is a form of energy since it makes the water particles to move and do work.

When we push a huge block, our body becomes

physics heat energy transfers heat energy heat, internal energy and work internal energy

  1. Hot

  2. Cold

  3. Charged

  4. Smaller

Show answer
Correct Option: A
Explanation:

When we push a huge rock, there is no transfer of muscular energy to the stationary rock.  

Also, there is no loss of energy because muscular energy transferred into heat energy, which causes our body to become hot.

Heat, as a form of energy, flows from

physics heat energy transfers heat energy heat, internal energy and work internal energy

  1. a body of higher heat content to that of a lower heat content

  2. a body of lower heat content to that of a higher heat content

  3. a hot body to a cold body

  4. a cold body to a hot body

Show answer
Correct Option: C
Explanation:

Heat flows from a hot body to a cold body. Heat flow has nothing to do with the total heat content of the body.

Amount of heat energy present is determined by :

physics heat energy transfers heat energy heat, internal energy and work internal energy

  1. Sum total of kinetic energy and the potential energy of its molecules

  2. Sum total of mechanical energy and surface energy of its molecules

  3. Sum total of chemical energy and potential energy of its molecules

  4. All

Show answer
Correct Option: A
Explanation:

The amount of heat energy present in a body is determined by the sum total of the kinetic energy and potential energy of its molecules.

Form of energy which causes in us sensation of hotness or coldness :

physics heat energy transfers heat energy heat, internal energy and work internal energy

  1. Surface energy

  2. Heat energy

  3. Kinetic energy

  4. Potential energy

Show answer
Correct Option: B
Explanation:

It is a form of energy which causes in us the sensation of hotness or coldness for ex. If we dip our finger in hot water we have sensation of hotness.

Heat is a from of ______

physics heat energy transfers heat energy heat, internal energy and work internal energy

  1. Energy

  2. Work

  3. Power

  4. None of these

Show answer
Correct Option: A
Explanation:

In thermodynamics, heat is a type of energy transfer in which energy flows from a warmer substance or object to a colder one. It can be defined as the total amount of transferred energy excluding any macroscopic work that was done and any transfer of part of the object itself Transfer of energy as heat can occur through direct contact, through a barrier that is impermeable to matter (as in conduction), by radiation between separated bodies, by way of an intermediate fluid (as in convective circulation), or by a combination of these By contrast to work, heat involves the stochastic (random) motion of particles (such as atoms or molecules) that is equally distributed among all degrees of freedom, while work is confined to one or more specific degrees of freedom such as those of the center of mass.

When heat energy is given out by a hot substance then the kinetic energy of its molecules _________. Fill in the blank. 

physics heat energy transfers heat energy heat, internal energy and work internal energy

  1. Increases

  2. Decreases

  3. Remain same

  4. None

Show answer
Correct Option: B
Explanation:

When heat energy is given out by a hot substance, the internal energy of the substance decreases hence kinetic energy of its molecules i.e. they become slower in motion.

Greater the heat energy, ________ the body. Fill in the blank.     

physics heat energy transfers heat energy heat, internal energy and work internal energy

  1. Hotter

  2. Colder

  3. Neutral

  4. None

Show answer
Correct Option: A
Explanation:

Greater heat energy of a body means molecules of the body are moving faster i.e. they have greater kinetic energy, which gives the higher temperature to the body i.e. body is hotter.

Which of the following is false for heat?

physics heat energy transfers heat energy heat, internal energy and work internal energy

  1. It is a form of energy.

  2. It cannot be seen but only can be felt.

  3. If a body's temperature is increased, it gains heat energy.

  4. It is always produced from chemical energy.

Show answer
Correct Option: D
Explanation:

Heat is a form of energy. It can only be felt and not seen. 

Heat transferred to a body is given by
$Q=ms\Delta T$
Hence, when temperature of body is increased, it gains heat energy. It flows from hotter body to colder body. Other forms of energy can also convert to heat energy. For example, for a sliding block on a rough surface, most of the kinetic energy is converted into heat energy.

At the molecular level what can be said about Heat energy?

physics heat energy transfers heat energy heat, internal energy and work internal energy

  1. Heat energy is equal to total mechanical energy of all its molecules

  2. Heat energy is equal to total potential energy of all its molecules

  3. Heat energy is equal to total kinetic energy of all its molecules

  4. Heat energy is equal to total heat energy of all its molecules

Show answer
Correct Option: A
Explanation:

At molecular level, heat energy is equal to mechanical energy of all molecules. Mechanical energy of the molecules is the sum of total Kinetic energy and potential energy of molecules.