Question
A point source of light B is placed at a distance L in front of the centre of a mirror of width d hung vertically on a wall. A man walks in front of the mirror along a line parallel to the mirror at a distance 2L from it as shown. The greatest distance over which he can see the image of the light source in the mirror is
- d/2
- d
- 2d
- 3d
The correct answer is: 3d
Related Questions to study
Figure shows a glowing mercury tube. The illuminances at point A, B and C are related as
Figure shows a glowing mercury tube. The illuminances at point A, B and C are related as
A block rests on a rough inclined plane making an angle 
of with the horizontal. The coefficient of static friction between the block and the plane is 0.8. If the frictional force on the block is 10 N, the mass of the block (in kg) is : 
A block rests on a rough inclined plane making an angle of with the horizontal. The coefficient of static friction between the block and the plane is 0.8. If the frictional force on the block is 10 N, the mass of the block (in kg) is :
In 
then the triangle is.
In then the triangle is.
Two masses 
tied to a string are hanging over a light friction less pulley. What is the acceleration of the masses when they are free to move ? (g=9.8
)
Two masses tied to a string are hanging over a light friction less pulley. What is the acceleration of the masses when they are free to move ? (g=9.8)
A machine gun fires a bullet of mass 40 g with a velocity 1200 
. The man holding it, can exert maximum force of 144 N on the gun. How many bullets can he fire per second at the most?
A machine gun fires a bullet of mass 40 g with a velocity 1200 . The man holding it, can exert maximum force of 144 N on the gun. How many bullets can he fire per second at the most?
One end of massless rope, which passes over a massless and frictionless pulley P is tied to a hook C while the other end is free. Maximum tension that the rope can bear is 840 N. With what value of maximum safe acceleration (in 
) can a man of 60 kg climb on the rope
One end of massless rope, which passes over a massless and frictionless pulley P is tied to a hook C while the other end is free. Maximum tension that the rope can bear is 840 N. With what value of maximum safe acceleration (in ) can a man of 60 kg climb on the rope
Three identical blocks of masses m = 2 kg are drawn by a force F with an acceleration of 0.6 ms–2 on a frictionless surface, then what is the tension (in N) in the string between the blocks B and C
Three identical blocks of masses m = 2 kg are drawn by a force F with an acceleration of 0.6 ms–2 on a frictionless surface, then what is the tension (in N) in the string between the blocks B and C
When forces 
are acting on a particle of mass m such that and are mutually perpendicular, then the particle remains stationary. If the force is now removed then the acceleration of the particle is-
When forces are acting on a particle of mass m such that and are mutually perpendicular, then the particle remains stationary. If the force is now removed then the acceleration of the particle is-
In above problem, the value(s) of F for which M and m are stationary with respect to
In above problem, the value(s) of F for which M and m are stationary with respect to
Consider a special situation in which both the faces of the block are smooth, as shown in adjoining figure. Mark out the correct statement(s)
Consider a special situation in which both the faces of the block are smooth, as shown in adjoining figure. Mark out the correct statement(s)
Imagine a situation in which the horizontal surface of block is smooth and its vertical surface is rough with a coefficient of friction 
In above problem, choose the correct value(s) of F which the blocks M and m remain stationary with respect to M0
Imagine a situation in which the horizontal surface of block is smooth and its vertical surface is rough with a coefficient of friction In above problem, choose the correct value(s) of F which the blocks M and m remain stationary with respect to M0
Imagine a situation in which the horizontal surface of block is smooth and its vertical surface is rough with a coefficient of friction Identify the correct statement(s)
Imagine a situation in which the horizontal surface of block is smooth and its vertical surface is rough with a coefficient of friction Identify the correct statement(s)
A solid sphere of mass 10 kg is placed over two smooth inclined planes as shown in figure. Normal reaction at 1 and 2 will be 
A solid sphere of mass 10 kg is placed over two smooth inclined planes as shown in figure. Normal reaction at 1 and 2 will be
The number of integral values of k for which the equation 
has a solution is
The number of integral values of k for which the equation has a solution is
in the interval 
is
