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A 60 watt bulb is hung over the center of a table 4 m cross times 4 m at a height of 3 m. The ratio of the intensities of illumination at a point on the centre of the edge and on the corner of the table is

  1. left parenthesis 17 divided by 13 right parenthesis to the power of 3 divided by 2 end exponent    
  2. 2/1    
  3. 17/13    
  4. 5/4    

The correct answer is: left parenthesis 17 divided by 13 right parenthesis to the power of 3 divided by 2 end exponent

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physics-General
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Water and turpentine oil (specific heat less than that of water) are both heated to same temperature. Equal amounts of these placed in identical calorimeters are then left in air

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because c subscript o i l end subscript less than c subscript W a t e r end subscript
rightwards double arrow open parentheses R a t e blank o f blank c o o l i n g close parentheses subscript o i l end subscript greater than open parentheses R a t e blank o f blank c o o l i n g close parentheses subscript W a t e r end subscript

It is clear that, at a particular time after start cooling, temperature of oil will be less than that of water
So graph B represents the cooling curve of oil and A represents the cooling curve of water

Water and turpentine oil (specific heat less than that of water) are both heated to same temperature. Equal amounts of these placed in identical calorimeters are then left in air

physics-General
As we know, Rate of cooling proportional to fraction numerator 1 over denominator s p e c i f i c blank h e a t left square bracket c right square bracket end fraction
because c subscript o i l end subscript less than c subscript W a t e r end subscript
rightwards double arrow open parentheses R a t e blank o f blank c o o l i n g close parentheses subscript o i l end subscript greater than open parentheses R a t e blank o f blank c o o l i n g close parentheses subscript W a t e r end subscript

It is clear that, at a particular time after start cooling, temperature of oil will be less than that of water
So graph B represents the cooling curve of oil and A represents the cooling curve of water