The latent heat of fusion of ice is 80 cal/g. Heat required to melt 50 g ice at 0°C is
A. 800 cal
B. 4000 cal
C. 40 cal
D. 1600 cal
Answer: Option B
Solution (By JKSSB Mock Tests)
Q = mL = 50 × 80 = 4000 cal. (1 cal = 4.2 J, but here in cal). No temperature change during phase change. Latent heat of vaporization is 540 cal/g for water.
Explanation:
Silicon semiconductor, abundant, efficient for photovoltaic cells. Also gallium arsenide. Solar cells convert light to electricity. Renewable energy technology.
Explanation:
Ship is made of steel (density > water) but hollow shape makes average density (including air) less than water. Displaced water weight equals ship's weight, buoyancy holds it up.
Explanation:
Newton's third law states: for every action, there is an equal and opposite reaction. These forces act on two different interacting bodies, hence they never cancel each other as they don't act on the same body. They can act at a distance (e.g., gravitational forces) or through contact. Cancellation of forces occurs only when multiple forces act on a single body. This distinction is crucial for free-body diagram analysis. Exam tip: Always identify which body each force acts upon. Misconception about force cancellation is a common trap in competitive exam questions testing Newton's laws.
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