The number of significant figures in 0.00250 is: MCQ with Answer and Explanation
Question
Report Error
Discuss this Question (0)
Practice More Physics Questions
Question #1
Report Error
The time taken for a ball dropped from height h to reach ground is t. If dropped from height 4h, the time taken is:
Correct Answer: Option C
Explanation:
Free fall: h = ½gt² ⇒ t = √(2h/g). Thus t ∝ √h. If h' = 4h, t' = √(4h/g) = 2√(h/g) = 2t. Time doubles when height quadruples. Memory aid: 'Free fall time: t ∝ √h; quadruple height ⇒ double time'. This kinematics proportional reasoning problem is frequently tested in competitive exams. Always derive the proportionality from fundamental equations; avoid assuming linear relationships for non-linear motion.
Free fall: h = ½gt² ⇒ t = √(2h/g). Thus t ∝ √h. If h' = 4h, t' = √(4h/g) = 2√(h/g) = 2t. Time doubles when height quadruples. Memory aid: 'Free fall time: t ∝ √h; quadruple height ⇒ double time'. This kinematics proportional reasoning problem is frequently tested in competitive exams. Always derive the proportionality from fundamental equations; avoid assuming linear relationships for non-linear motion.
Question #2
Report Error
According to Brewster's Law, when unpolarized light is incident on a transparent medium at the polarizing angle (Brewster's angle), the reflected and refracted rays are:
Correct Answer: Option C
Explanation:
Brewster's Law states that when light hits a dielectric boundary at a specific angle of incidence (Brewster's angle, theta_p), the reflected light is completely plane-polarized. At this exact geometric condition, the angle between the reflected ray and the refracted (transmitted) ray is strictly 90 degrees.
Brewster's Law states that when light hits a dielectric boundary at a specific angle of incidence (Brewster's angle, theta_p), the reflected light is completely plane-polarized. At this exact geometric condition, the angle between the reflected ray and the refracted (transmitted) ray is strictly 90 degrees.
Question #3
Report Error
Carnot efficiency η = 1 - T₂/T₁. If T₁=600K, T₂=300K, η is:
No comments yet. Be the first to start the discussion!