Question 1
A particle moves in a circle of radius R with a constant speed v. The work done by the centripetal force in one complete revolution is:
Explanation:
Work done is the dot product of Force and Displacement. Centripetal force acts perpendicular to the displacement at every instant, so the work done is zero.
Work done is the dot product of Force and Displacement. Centripetal force acts perpendicular to the displacement at every instant, so the work done is zero.
Question 2
The dimensional formula for Plank's constant (h) is:
Explanation:
E = hv => h = E/v. Dimensions of E are [ML²T⁻²] and frequency v are [T⁻¹]. So h = [ML²T⁻²] / [T⁻¹] = [ML²T⁻¹].
E = hv => h = E/v. Dimensions of E are [ML²T⁻²] and frequency v are [T⁻¹]. So h = [ML²T⁻²] / [T⁻¹] = [ML²T⁻¹].
Question 3
Two resistors of 6Ω and 3Ω are connected in parallel. The equivalent resistance is:
Explanation:
For parallel combination: 1/Req = 1/R1 + 1/R2 = 1/6 + 1/3 = 3/6 = 1/2. So Req = 2Ω.
For parallel combination: 1/Req = 1/R1 + 1/R2 = 1/6 + 1/3 = 3/6 = 1/2. So Req = 2Ω.