A refrigerator is to maintain eatables kept inside at `9^(@)C`. If room temperature is `36^(@)C`, calculate the coefficient of performance.

A clock with an iron pendulum keeps correct time at 15^(@)C . If th room temperature rises to 20^(@)C , the error in second per day will be (coefficient of linear expansion of iron is 0.000012^(@)C )

A clock , with a brass pendulum, keeps correct time at 20^(@)C , but loses 8.212 s per day , when the temperature rises to 30^(@)C . Calculate the coefficient of linear expansion of brass.

A U-tube contains mercury, one of its limbs is at 0^(@)C and another is at 100^(@) C . If the height of the column of mercury at lower temperature is 60 cm and that of column of mercury at higher temperature is 1.2 cm greater, calculate the coefficient of real expansion of mercury (in 10^(-4) per ""^(@) C )