| ⇦ | 
| ⇨ |
A person wants a real image of his own, 3 times enlarged. Where should he stand in front of a concave mirror of radius of curvature of 30 cm?
Options
(a) 90 cm
(b) 10 cm
(c) 20 cm
(d) 30 cm
Correct Answer:
20 cm
Explanation:
Given, m = -3 and R = 30 cm
f = -(R / 2) = -15 cm
We know that, m = -(v / u) ⇒ -3 = -v / u
Therefore, v= 3u
1/f = (1/v) + (1/u) ⇒ (1/-15) = (1/3u) + (1/u) = (1+3) / 3u
-3u = 4 × 15
u = (-4 × 15) / 3
Initial position of a person, u = -20 cm
Related Questions: - A bar magnet has a coercivity of 4×10³ Am⁻¹. It is placed inside a solenoid
- An atom bomb weighing 1 kg explodes releasing 9×10¹³ J of energy.
- A spring balance is attached to the ceiling of a lift.A man hangs his bag on the spring
- Two racing cars of masses m₁ and m₂ are moving in circles of radii
- Two lines of force due to a bar magnet
Topics: Ray Optics
(94)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- A bar magnet has a coercivity of 4×10³ Am⁻¹. It is placed inside a solenoid
- An atom bomb weighing 1 kg explodes releasing 9×10¹³ J of energy.
- A spring balance is attached to the ceiling of a lift.A man hangs his bag on the spring
- Two racing cars of masses m₁ and m₂ are moving in circles of radii
- Two lines of force due to a bar magnet
Topics: Ray Optics (94)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
18000+ students are using NEETLab to improve their score. What about you?
Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.
Share this page with your friends
Leave a Reply