Tag: physics

Questions Related to physics

The intensity of the atmospheric electric field is, normally,

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

  1. greater in the middle of the day than at morning

  2. smaller in the middle of the day than at morning

  3. same in the middle of the day as at morning

  4. zero in the middle of the day and at morning

Show answer
Correct Option: A
Explanation:

The fine day net positive charge sets up an electric field between the negative earth and the net positive charge in the air and this electric field stores electrical energy. The positive charge acts by induction on the earth and electromagnetic devices.

The explanation for atmospheric electricity mainly lies in the field of

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

  1. electromagnetism

  2. electrostatics

  3. current electricity

  4. All of the above

Show answer
Correct Option: B
Explanation:
The phenomenon of atmospheric electricity is observed mainly explained by the presence of static charges in various object. The neutralisation effect of these charges can be seen as atmospheric electricity. And the study of static charges is known as electrostatics

Which of the following is an example of atmospheric electricity?

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

  1. Auroras

  2. Lightening

  3. Ionospheric currents

  4. All of the above

Show answer
Correct Option: D
Explanation:
Examples of atmospheric electricity
(a) Auroras $\rightarrow$ appearance of streamer of reddish light in the sky, especially near northern or southern magnetic pole.
(b) Lightning
(c) Ionospheric currents

When there is lightning and 
a) You are in a jungle ,go under a tall tree.
b) You are in a jungle,go under a canopy of small trees and bushes.
c) You are out in the open,crouch on your feet,do not stand up or lie on the ground.
d) You are in an open field,stay there rather than go inside a completely covered building.Of these the good strategies are :-  

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

  1. B and C

  2. A and C

  3. A,B and C

  4. A,C and D

Show answer
Correct Option: A
Explanation:

When there is lightning and you are in a jungle, its better to go under a canopy of small trees and bushes. The electric field is strongest near the pointed tip of an electrical conductor, and so isolated trees often make for great targets for lightning strikes. Canopy of small trees delocalises charge concentration on the other hand. 

Standing out in a field far from trees may also pose risks too as it makes you  the tallest object around and may be a target for lightning strikes. The idea will be to crouch low so that you are not the tallest object around, and at the same time keep your feet close together with your heels touching. This will help the electricity to go in one foot and out the other.

The intensity of atmospheric electric field is :

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

  1. same in winter as in summer

  2. lesser in winter than in summer

  3. greater in winter than in summer

  4. none of the above

Show answer
Correct Option: C
Explanation:
Experiments have shown that the intensity of the electric field is greater in the middle of the day than at morning or night and is also greater in winter than in summer, which is totaly based on 'Fine weather' theory.

There are $4\times 10^{23}$ atoms in a metal sphere. If one electron is removed from 0.1% atom. what will be the charge on the sphere?

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

  1. $64C$

  2. $6.4C$

  3. $0.64C$

  4. $-6.4C$

Show answer
Correct Option: A

Clouds get electrically charged when :

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

  1. The UV rays of sun falls on them

  2. Air molecules rub against water molecules

  3. Cold currents of air rub against hot currents of air

  4. Both B and C

Show answer
Correct Option: D
Explanation:

The heat from the sun and warm air cause water from water bodies to vaporize. These vapour accumulate in the sky to form clouds. When these vapour molecules rub against the air molecules or other vapour molecules, they acquire charge due to friction.

Lightning occurs when an electrical charge is built up within a cloud, due to static electricity generated by supercooled water droplets colliding with ice crystals near the freezing level. When a large enough charge is built up, a large discharge will occur and can be seen as lightning. The temperature of a lightning bolt can be five times hotter than the surface of the sun. 

Both B and C are correct.
Option D 

A lightning rocket is a device used to control 

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

  1. time and location of a lighting strike.

  2. fuel and location of a lighting strike.

  3. the lighting of the strom

  4. none of the above

Show answer
Correct Option: A
Explanation:

A lightening rocket is a rocket device, about the size of a man, that trails behind a conductor, such as fine copper wire. It is therefore, a conducting lightening rod which is grounded and positioned along side the launch tube in communication with the conductive path to thereby control time and location of a lightening strike from the thundercloud.

Which of the following statement is correct?

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

  1. The earth's surface is negatively charged

  2. The earth's surface is positively charged

  3. The earth's surface is neutral

  4. None of the above

Show answer
Correct Option: A
Explanation:

The earth's surface is negatively charged.


Answer-(A)

Electric discharges in the atmosphere is associated with natural phenomena such as :

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

  1. lightning

  2. reflecting

  3. refracting

  4. none of the above

Show answer
Correct Option: A
Explanation:

$Lightning$ is the natural phenomena of electric discharge through atmosphere.


Answer-(A)