SONAR uses waves of frequency: MCQ with Answer and Explanation

Explanation:
Least count = 1 MSD - 1 VSD. 20 VSD = 19 MSD ⇒ 1 VSD = 19/20 mm = 0.95 mm. LC = 1 - 0.95 = 0.05 mm. Formula: LC = MSD/n where n = vernier divisions. Memory tip: LC = smallest measurable difference = main scale value/vernier divisions. Essential for practical physics questions in competitive exams.

Explanation:
Dynamo/generator converts mechanical to electrical energy using induction.

Explanation:
Escape velocity v_e = √(2GM/R), where M is planet mass, R its radius. Thus v_e depends on both M and R. It is independent of the escaping body's mass (as gravitational and inertial mass cancel). Memory tip: 'v_e ∝ √(M/R); larger M or smaller R ⇒ higher escape velocity'. This gravitation formula application is frequently tested in competitive exams. Always recall that escape velocity is a property of the planet, not the projectile. This problem assesses understanding of gravitational potential energy concepts.