Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev

DC Pandey (Questions & Solutions) of Physics: NEET

Created by: Ciel Knowledge

NEET : Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev

The document Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev is a part of the NEET Course DC Pandey (Questions & Solutions) of Physics: NEET.
All you need of NEET at this link: NEET

Introductory Exercise 27.1

Ques 1: Show that the unit of Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev is m/s.
Sol:
 Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev = Speed of light in vacuum.

Ques 2: The magnetic field in a plane electromagnetic wave is given by (SI units)
By = (2 × 10-7 T) sin [500 x + 1.5 × 1011 t]
(a) What is the wavelength and frequency of the wave?
(b) Write an expression for the electric field vector.
Ans:
 Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
= 0.0125 m= 1.25 cm
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
= 2.39 × 1010Hz
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
E0 = cB0
= (3 × 108)(2 × 10-7) = 60 V/m
kx and ωt have same sign. Therefore, electromagnetic wave is travelling along negative x direction. Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev are in mutually perpendicular direct ions. Hence oscillations Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev of are along z-direction.

Introductory Exercise 27.2

Ques 1: Prove that for any value of angle i, rays 1 and 2 are parallel.
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
Sol: 
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
PQ and MN are mutually parallel. Rays 1 and 2 are making equal angles (= ∠i) from PQ and MN. So, they are mutually parallel.

Ques 2: A man approaches a vertical plane mirror at speed of 2 m/s. At what rate does he approach his image?
Sol: 
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev

Ques 3: A pole of height 4 m is kept in front of a vertical plane mirror of length 2 m. The lower end of the mirror is at a height of 6 m from the ground. The horizontal distance between the mirror and the pole is 2 m. Up to what minimum and maximum heights a man can see the image of top of the pole at a horizontal distance of 4 m (from the mirror) standing on the same horizontal line which is passing through the pole and the horizontal point below the mirror?
Sol:

Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
PQ = Pole
MN = Image of pole
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
Minimum height required = AD = BD + AD = 10m
Further,
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
Maximum height required = AE = BE+ AB = 16 m

Introductory Exercise 27.3

Ques 1: Assume that a certain spherical mirror has a focal length of- 10.0 cm. Locate and describe the image for object distances of
(a) 25.0 cm (b) 10.0 cm (c) 5.0 cm.
Sol:
Apply Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
(a) f = -10 cm, u = - 25 cm Solving we get, v = -16.7cm
Since, v is negative, image is in front of mirror. So it is real. Similarly, we can solve for other parts.

Ques 2: A ball is dropped from rest 3.0 m directly above the vertex of a concave mirror that has a radius of 1.0 m and lies in a horizontal plane.
(a) Describe the motion of ball's image in the mirror.
(b) At what time do the ball and its image coincide?
Sol: 
(a) From O to F, image is real.
From F to P, image is virtual.
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
At O
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
v = - 0.6 m

(b) When object is at C and P, image coincides with object. Using,
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
or  Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev

Ques 3: A spherical mirror is to be used to form on a screen 5.0 m from the object an image five times the size of the object.
(a) Describe the type of mirror required.
(b) Where should the mirror be positioned relative to the object?
Sol: 
(a) Image has to be taken on a screen. So it should be real. Hence mirror should be concave.
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
Image is 5 times magnified. Hence, | v | = 5 | u |
or
(5 + x) = 5x
Solving we get, x = 1.25 cm
Now using, Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
We have, Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
Solving we get, R = - 2.08 m

Ques 4: Figure shows two rays P and Q being reflected by a mirror and going as F and Q'. State which type of mirror is this?
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
Sol:
Reflected rays are neither converging nor diverging. Hence, mirror is plane.

Ques 5: The following table shows object distance, object size, and mirror focal length (all in centimeters) for various situations. Use ray tracing to determine the image size and location for each case.
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
Sol: 
Let us draw the ray diagram for the first part.
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
In ΔO1O2P and ΔP I1I2 we have,
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
or
x = (20)(I1,I2) ...(i)
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
In ΔO1O2C and l1I2 C we have, Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
or (40 - x) = 40(I1I2) ....(ii)
Solving Eqs. (i) and (ii) we get,  Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev

Ques 6: Complete the following table for spherical mirrors. All distances are in centrimeters.

Mirror Type

Radius

Focal Length

Object Distance

Image Distance

Lateral Magnification

Real/Virtual Image


-2540





20-30



+15
+30




20
-2.0

+20

-40



-10

+2.0

Sol: Negative focal length means concave mirror and positive focal length means convex mirror.
Apply, Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
And   Reflection of Light - Physics, Solution by DC Pandey NEET Notes | EduRev
Further, if v is negative then image is in front of mirror. So, it is real and inverted.
R = 2f

Offer running on EduRev: Apply code STAYHOME200 to get INR 200 off on our premium plan EduRev Infinity!

Complete Syllabus of NEET

Dynamic Test

Content Category

Related Searches

Solution by DC Pandey NEET Notes | EduRev

,

ppt

,

Extra Questions

,

Free

,

video lectures

,

Sample Paper

,

Semester Notes

,

practice quizzes

,

study material

,

past year papers

,

mock tests for examination

,

Exam

,

Objective type Questions

,

Previous Year Questions with Solutions

,

pdf

,

Reflection of Light - Physics

,

Viva Questions

,

Summary

,

MCQs

,

Reflection of Light - Physics

,

Reflection of Light - Physics

,

Solution by DC Pandey NEET Notes | EduRev

,

Important questions

,

Solution by DC Pandey NEET Notes | EduRev

,

shortcuts and tricks

;