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Q:

Lightning is produced when 

A) Similar charges of electricity rush towards each other and then get repelled B) clouds strike against impurities in air and the friction burns up these impurities
C) strong opposite charges in different clouds break down the resistance offered by the intervening air D) water vapour produces electricity in the clouds

Answer:   C) strong opposite charges in different clouds break down the resistance offered by the intervening air

Explanation:

When the resistance of the air between breaks down the current flows from the positive cloud to the negative cloud in a flash which we call lightning . The difference of potential involves is very high.

Subject: Physics
Q:

Which is best used as a sound absorbing material in partition walls ?

A) Stone chips B) Steel
C) Glass - wool D) Glass pieces
 
Answer & Explanation Answer: C) Glass - wool

Explanation:

Materials that do not transfer mechanical energy well. These tend to be soft,flexible, low density, and with high surface area to linear area ratios.

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Exam Prep: AIEEE

3 152
Q:

On which day ' National Science Day ' is celebrated in India ?

A) February 23 B) February 25
C) February 26 D) February 28
 
Answer & Explanation Answer: D) February 28

Explanation:

National Science Day is celebrated in India on 28 February each year to mark the discovery of the Raman effect by Indian physicist Sir Chandrashekhara Venkata Raman on 28 February 1928.

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Exam Prep: Bank Exams , CAT
Job Role: Bank Clerk

6 112
Q:

The capacity of a pure capacitor is 1 farad. In D.C circuit, its effective resistance will be

A) Zero B) Infinite
C) 1 Ohm D) 1/2 Ohm
 
Answer & Explanation Answer: B) Infinite

Explanation:
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4 421
Q:

A convex mirror is used to form an image of a real object. The image

A) is diminished in size B) is erect
C) always lies between the pole and the focus D) all of the above
 
Answer & Explanation Answer: D) all of the above

Explanation:
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5 259
Q:

The quality of sound produced by an instrument depends on the

A) Frequency B) Intensity
C) Number of overtones D) None of these
 
Answer & Explanation Answer: C) Number of overtones

Explanation:
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3 284