For the following questions answer them individually
The working temperatures in evaporator and condensercoils of a refrigerator are $$-25^\circ C$$ and $$30^\circ C$$, respectively. The COP of the refrigerator is 0.85 of the maximum COP for a power input of 2 kW. The refrigeration effect produced will be
A mercury thermometer was first placed in melting ice and the length of mercury column was observed to be 10 mm; when it was placed in steam, the length of the column was
250 mm. Whenplaced in tap water, the length of the column was 58 mm. The temperature of the tap water is
The amountof steam (at $$100^\circ C$$) required to raise the temperature of 200 g of water from $$60^\circ C$$ to $$100^\circ C$$ is
A engine works on Carnot cycle between $$727^\circ C$$ and $$227^\circ C$$. The efficiency of the engine is
A boat which has a speed of 5 km/h in still water crosses a river of width 1 km along the shortest path in 15 min. The velocity of the river in km/h is
In 1s, a particle goes from point A to point B, moving in a semicircle (as shown in figure). The magnitude of the average velocity is
A block is made to slide down an inclined plane ($$30^\circ$$ with horizontal) which is smooth. It starts sliding from rest and takes a time ‘t’ to reach the bottom of the plane. An identical bodyis freely dropped from the same point. The time the body takes to reach the bottom is