Physics-
General
Easy
Question
A light ray I is incident on a plane mirror M. The mirror is rotated in the direction as shown in the figure by an arrow at frequency 
rps. The light reflected by the mirror is received on the wall W at a distance 10 m from the axis of rotation. When the angle of incidence becomes 
the speed of the spot (a point) on the wall is:
- 10 m/s
- 1000 m/s
- 500 m/s
- None of these
The correct answer is: 1000 m/s
Related Questions to study
physics-
A plano concave lens is placed on a paper on which a flower is drawn. How far above its actual position does the flower appear to be?
A plano concave lens is placed on a paper on which a flower is drawn. How far above its actual position does the flower appear to be?
physics-General
physics-
The figure shows a parallel slab of refractive index 
which is surrounded by media of refractive indices 
and 
. Light is incident on the slab at angle of incidence 
. The time taken by the ray to cross the slab is ' 
if incidence is from ' ' and it is ' 
' if the incidence is from ' '. Then assuming that 
and 
, then value of 
.
The figure shows a parallel slab of refractive index which is surrounded by media of refractive indices and . Light is incident on the slab at angle of incidence . The time taken by the ray to cross the slab is ' if incidence is from ' ' and it is ' ' if the incidence is from ' '. Then assuming that and , then value of .
physics-General
physics-
Two blocks each of mass m lie on a smooth table. They are attached to two other masses as shown in the figure. The pulleys and strings are light. An object O is kept at rest on the table. The sides AB & CD of the two blocks are made reflecting. The acceleration of two images formed in those two reflecting surfaces w.r.t. each other is:
Two blocks each of mass m lie on a smooth table. They are attached to two other masses as shown in the figure. The pulleys and strings are light. An object O is kept at rest on the table. The sides AB & CD of the two blocks are made reflecting. The acceleration of two images formed in those two reflecting surfaces w.r.t. each other is:
physics-General
physics-
In the figure shown, the image of a real object O is formed at point I. AB is the principal axis of the mirror. The mirror must be:
In the figure shown, the image of a real object O is formed at point I. AB is the principal axis of the mirror. The mirror must be:
physics-General
physics-
A transparent cylinder has its right half polished so as to act as a mirror. A paraxial light ray is incident from left, that is parallel to principal axis, exits parallel to the incident ray as shown in the figure. The refractive index n of the material of the cylinder is :
A transparent cylinder has its right half polished so as to act as a mirror. A paraxial light ray is incident from left, that is parallel to principal axis, exits parallel to the incident ray as shown in the figure. The refractive index n of the material of the cylinder is :
physics-General
chemistry-
Which of the following statements are true (or) false -
i) 
and 
are coordination isomers
ii) 
and 
are ionisation isomers
iii) 
and 
are linkage isomers
iv) cis platin exhibits geometrical isomerism
Which of the following statements are true (or) false -
i) and are coordination isomers
ii) and are ionisation isomers
iii) and are linkage isomers
iv) cis platin exhibits geometrical isomerism
chemistry-General
physics-
As shown in the figure the observer 'O' sees the distance AB as infinitely large. If refractive index of liquid is m1 and that of glass is 
As shown in the figure the observer 'O' sees the distance AB as infinitely large. If refractive index of liquid is m1 and that of glass is
physics-General
physics-
In the figure ABC is the cross section of a right angled prism and ACDE is the cross section of a glass slab. The value of 
so that light incident normally on the face AB does not cross the face AC is (given 
)
In the figure ABC is the cross section of a right angled prism and ACDE is the cross section of a glass slab. The value of so that light incident normally on the face AB does not cross the face AC is (given )
physics-General
physics-
A man starting from point P crosses a 4 km wide lagoon and reaches point Q in the shortest possible time by the path shown in the figure. If the person swims at a speed of 3 km/hr and walks at a speed of 4 km/hr, then his time of journey is (µsaltwater = 4/3) :
A man starting from point P crosses a 4 km wide lagoon and reaches point Q in the shortest possible time by the path shown in the figure. If the person swims at a speed of 3 km/hr and walks at a speed of 4 km/hr, then his time of journey is (µsaltwater = 4/3) :
physics-General
physics-
The following figure represents a wave front AB which passes from air to another transparent medium and produces a new wave front CD after refraction. The refractive index of the medium is (PQ is the boundary between air and the medium).
The following figure represents a wave front AB which passes from air to another transparent medium and produces a new wave front CD after refraction. The refractive index of the medium is (PQ is the boundary between air and the medium).
physics-General
physics-
Two plane mirrors are joined together as shown in the figure. Two point objects 
and 
are placed symmetrically such that 
. The image of the two objects is common if :
Two plane mirrors are joined together as shown in the figure. Two point objects and are placed symmetrically such that . The image of the two objects is common if :
physics-General
physics-
An object and a plane mirror are shown in figure. Mirror is moved with velocity V as shown. The velocity of image is :
An object and a plane mirror are shown in figure. Mirror is moved with velocity V as shown. The velocity of image is :
physics-General
physics-
In the figure shown a person AB of height 170 cm is standing infront of a plane mirror. His eyes are at height 164 cm. At what distance from P should a hole be made in the mirror so that he cannot see the top of his head.
In the figure shown a person AB of height 170 cm is standing infront of a plane mirror. His eyes are at height 164 cm. At what distance from P should a hole be made in the mirror so that he cannot see the top of his head.
physics-General
physics-
A small object is placed 50 cm to the left of a thin convex lens of focal length 30 cm. A convex spherical mirror of radius of curvature 100 cm is placed to the right of the lens at a distance of 50 cm. The mirror is tilted such that the axis of the mirror is at an angle 
to the axis of the lens, as shown in the figure.
If the origin of the coordinate system is taken to be at the centre of the lens, the coordinates (in cm) of the point (x,y) at which the image is formed are
A small object is placed 50 cm to the left of a thin convex lens of focal length 30 cm. A convex spherical mirror of radius of curvature 100 cm is placed to the right of the lens at a distance of 50 cm. The mirror is tilted such that the axis of the mirror is at an angle to the axis of the lens, as shown in the figure.
If the origin of the coordinate system is taken to be at the centre of the lens, the coordinates (in cm) of the point (x,y) at which the image is formed are
physics-General
physics-
Light guidance in an optical fiber can be understood by considering a structure comprising of thin solid glass cylinder of refractive index surrounded by a medium of lower refractive index . The light guidance in the structure takes place due to successive total internal reflections at the interface of the media and as shown in the figure. All rays with the angle of incidence i less than a particular value im are confined in the medium of refractive index . The numerical aperture (NA) of the structure is defined as sin im .
For two structures namely S1 with 
and 
and 
and taking the refractive index of water to be 4/3 and that of air to be 1, the correct option (s) is (are)
Light guidance in an optical fiber can be understood by considering a structure comprising of thin solid glass cylinder of refractive index surrounded by a medium of lower refractive index . The light guidance in the structure takes place due to successive total internal reflections at the interface of the media and as shown in the figure. All rays with the angle of incidence i less than a particular value im are confined in the medium of refractive index . The numerical aperture (NA) of the structure is defined as sin im .
For two structures namely S1 with and and and taking the refractive index of water to be 4/3 and that of air to be 1, the correct option (s) is (are)
physics-General
