A body starts from rest and moves with uniform acceleration a. The ratio of distances covered in the 1st, 2nd, and 3rd seconds of motion is: MCQ with Answer and Explanation
Question
Report Error
Discuss this Question (0)
Practice More Physics Questions
Question #1
Report Error
The acceleration due to gravity on Earth's surface is g. At a height equal to Earth's radius above the surface, g' will be:
Correct Answer: Option B
Explanation:
Acceleration due to gravity at height h: g' = gR²/(R+h)², where R is Earth's radius. Given h = R, so g' = gR²/(2R)² = gR²/4R² = g/4. This inverse square law dependence arises from Newton's law of gravitation. At depth, variation differs, but for height, this formula applies. Memory aid: Double the distance from center ⇒ gravity becomes one-fourth. This standard result is frequently tested in gravitation sections of competitive exams. Always verify whether height or depth is specified, as formulas differ significantly.
Acceleration due to gravity at height h: g' = gR²/(R+h)², where R is Earth's radius. Given h = R, so g' = gR²/(2R)² = gR²/4R² = g/4. This inverse square law dependence arises from Newton's law of gravitation. At depth, variation differs, but for height, this formula applies. Memory aid: Double the distance from center ⇒ gravity becomes one-fourth. This standard result is frequently tested in gravitation sections of competitive exams. Always verify whether height or depth is specified, as formulas differ significantly.
Question #2
Report Error
The slope of a displacement-time graph for uniform motion is
Correct Answer: Option C
Explanation:
Displacement-time graph slope = Δx/Δt = average velocity. For uniform motion, velocity constant, graph is a straight line, slope equals velocity. Acceleration would be slope of velocity-time graph. Thus, slope represents velocity. Exam trick: slope of x-t graph gives instantaneous velocity.
Displacement-time graph slope = Δx/Δt = average velocity. For uniform motion, velocity constant, graph is a straight line, slope equals velocity. Acceleration would be slope of velocity-time graph. Thus, slope represents velocity. Exam trick: slope of x-t graph gives instantaneous velocity.
Question #3
Report Error
The phenomenon of total internal reflection occurs when light travels from:
Correct Answer: Option B
Explanation:
Total internal reflection (TIR) requires: (1) light travels from denser to rarer medium (n₁ > n₂), and (2) angle of incidence exceeds critical angle θ_c = sin⁻¹(n₂/n₁). Option A describes refraction toward normal; B describes partial reflection/refraction; D is incorrect. Memory aid: 'TIR: denser→rarer AND i > θ_c'. This condition-based question tests optics fundamentals, frequently examined in competitive exams. Always verify both conditions for TIR; common applications include optical fibers and prisms in binoculars.
Total internal reflection (TIR) requires: (1) light travels from denser to rarer medium (n₁ > n₂), and (2) angle of incidence exceeds critical angle θ_c = sin⁻¹(n₂/n₁). Option A describes refraction toward normal; B describes partial reflection/refraction; D is incorrect. Memory aid: 'TIR: denser→rarer AND i > θ_c'. This condition-based question tests optics fundamentals, frequently examined in competitive exams. Always verify both conditions for TIR; common applications include optical fibers and prisms in binoculars.
No comments yet. Be the first to start the discussion!