I. Friction depends on the nature of the surfaces in contact

II. Friction depends on the area of contact

III. Friction always acts in the direction of motion.

A. I only
B. II only
C. III only
D. I and II only
E. I,II and III

Correct Answer:

Option A – I only 

SEE ALSO  Calculate the length of a constantan wire of cross-sectional area 4 Ï€ x 10-8m² and resistivity 1.1 x 10-6 Ω m required to construct a standard resistor of resistance 21 Ω. [Take Ï€ = 22/7]

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