Tag: physics

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Multiple choice physics energy transformations and energy transfers law of conservation of energy the law of conservation of energy types of energy

According to the law of conservation of energy:

  1. energy exists in only one form

  2. energy can be created but not destroyed and it can be transformed from one form to another

  3. energy exists in many forms but it cannot be transformed

  4. energy can neither be produced nor be destroyed and it can be transformed from one form to another
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The law of conservation of energy states that the total amount of energy in a system remains constant ("is conserved"), although energy within the system can be changed from one form to another or transferred from one object to another.

Energy cannot be created or destroyed, but it can be transformed.

Multiple choice physics energy transformations and energy transfers law of conservation of energy the law of conservation of energy types of energy

According to law of conservation of energy :

  1. energy can be created but not destroyed and it can be transformed from one form into another

  2. energy exists in only one form

  3. energy exists in many forms but it cannot be transformed

  4. energy can neither be created nor be destroyed but can be changed into different forms
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$Law\ of conservation\ of\ energy$ states that the total energy of an isolated system remains constant and it is said to be conserved over time. Energy can neither be created nor be destroyed, but it can be transformed from one form to another, for instance, chemical energy can be converted to kinetic energy in the explosion of a stick of dynamite.

Multiple choice physics some natural phenomena how lightning occurs? the story of lightning advanced of lightning

State whether the given statement is True or False :

Lightning conductor cannot protect a building from lightning.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Answer is False.

The use of a lightning rod on a building protects the building by preventing the lightning strike. The idea is based upon the principle that the electric field strength is great around a pointed object. The intense electric fields surrounding a pointed object serve to ionize the surrounding air, thus enhancing its conductive ability. 
As a storm cloud approaches, there is a conductive pathway established between the statically charged cloud and the lightning rod. The static charges gradually migrate along this pathway to the ground, thus reducing the likelihood of a sudden and explosive discharge. 
The primary role of a lightning rod is to discharge the cloud over a longer length of time, thus preventing the excessive charge buildup that is characteristic of a lightning strike.
Hence, lightning conductor is a device to protect a building against lightning.

Multiple choice physics some natural phenomena how lightning occurs? the story of lightning advanced of lightning

Fill in the blanks:

During the development of a thunder-storm, the air currents move ________ while the water droplets move _______.

  1. downward, upward

  2. upward, downward

  3. downward, downward

  4. upward, upward
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Thunder-storm occurs due to vigorous movements of air currents upward and water droplets downward. This leads to separation of charges.

Multiple choice physics some natural phenomena how lightning occurs? the story of lightning advanced of lightning

It is safer to use mobile and cordless phone during lightning because?

  1. They are wireless

  2. Less chances of getting in contact with lightning

  3. Both a & b

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lightning can travels through the wires or cords of telephone giving electric shock to you but use of mobile and cordless phones are safe.

Multiple choice physics winds, storms and cyclones wind and rain example of some natural phenomena uneven heating of earth

Ocean thermal energy is due to 

  1. temperature difference at different levels in the ocean

  2. tides in the ocean

  3. energy stored by the water waves

  4. pressure different at different levels in the ocean
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Different temperature at different levels of ocean.

The sun’s heat warms the surface water a lot more than the deep ocean water, which creates the ocean’s naturally available temperature gradient, or thermal energy.

Multiple choice physics winds, storms and cyclones wind and rain example of some natural phenomena uneven heating of earth

Wind currents are generated due to:

  1. Uneven heating between the equator and the poles

  2. Change in atmospheric pressure

  3. Thunderstorm

  4. Cyclone
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The correct answer is option(A).

We know poles are cooler than equator as highest intensity of the sun's heat and light falls on the equator and it reduces as we go either side of the equator towards the poles. Cooler air from the surrounding areass of the equator comes towards the equator to fill the place of warm air which rises up due to sun's heating. Hence, wind currents are generated due to uneven heating.