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The coefficient of performance of a refr...

The coefficient of performance of a refrigerator is 5. If the temperature inside freezer is `- 20^@ C`, the temperature of the surroundings to which it rejects heat is _____

A

`21^@C`

B

`31^@C`

C

`41^@C`

D

`11^@C`

Text Solution

Verified by Experts

The correct Answer is:
B
Coefficient of performance of a refrigerator
`=T_L/(T_H-T_L)`
where `T_L` = lower temperature in K
`T_H`=higher temperature in K
`therefore 5=T_L/(T_H-T_L)`
`therefore 5T_H-5T_L=T_L`
`therefore 5T_H=6T_L`
`=6/5xx(273-20)`
`=6/5xx253`
=303.6 K
`therefore T_H`=303.6-273=`30.6^@C approx 31^@C`
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