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A lamp rated at  hangs over the middle of a round table with diameter  at a height of . It is replaced by a lamp of  and the distance to the table is changed so that theillumination at the centre of the table remains as before. The illumination at edge of the table becomes  times the original. Then  is

a)

b)

c)

1/4

d)



Question ID - 152546 | SaraNextGen Top Answer

A lamp rated at  hangs over the middle of a round table with diameter  at a height of . It is replaced by a lamp of  and the distance to the table is changed so that theillumination at the centre of the table remains as before. The illumination at edge of the table becomes  times the original. Then  is

a)

b)

c)

1/4

d)

1 Answer
127 votes
Answer Key / Explanation : (a) -

(a)

Case I

and

Case II

so

127 votes


127