Physics-
General
Easy
Question
A bird in air is diving vertically over a tank with speed 5cm/s Base of the tank is silvered A fish in the tank is rising upward along the same line with speed 2cm/s Water level is falling at a rate of 2cm/s 
Speed of the image of fish as seen by the bird directly in cm/s is
- 8
- 6
- 3
- 4
The correct answer is: 6
Related Questions to study
physics-
A Ray of light goes from A in a medium where the speed of light is V1 to a point B in a medium where the speed of light is V2 as shown in figure The path of the rays as shown in figure Answer the following questions,based on the above paragraph The slope of 
curve is
A Ray of light goes from A in a medium where the speed of light is V1 to a point B in a medium where the speed of light is V2 as shown in figure The path of the rays as shown in figure Answer the following questions,based on the above paragraph The slope of curve is
physics-General
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A Ray of light goes from A in a medium where the speed of light is V1 to a point B in a medium where the speed of light is V2 as shown in figure The path of the rays as shown in figure Answer the following questions,based on the above paragraph The time taken for the light to go from the point A to the point B in the figure
A Ray of light goes from A in a medium where the speed of light is V1 to a point B in a medium where the speed of light is V2 as shown in figure The path of the rays as shown in figure Answer the following questions,based on the above paragraph The time taken for the light to go from the point A to the point B in the figure
physics-General
physics-
Spherical aberration in spherical mirrors is a defect which is due to dependence of focal length ‘f’ on angle of incidence ‘ q ’ as shown in figure is given by 
where R is radius of curvature of mirror and q is the angle of incidence The rays which are closed to principal axis are called paraxial rays and the rays far away from principal axis are called marginal rays As a result of above dependence different rays are brought to focus at different points and the image of a point object is on a point Which of the following statements are correct regarding spherical aberration :
Spherical aberration in spherical mirrors is a defect which is due to dependence of focal length ‘f’ on angle of incidence ‘ q ’ as shown in figure is given by where R is radius of curvature of mirror and q is the angle of incidence The rays which are closed to principal axis are called paraxial rays and the rays far away from principal axis are called marginal rays As a result of above dependence different rays are brought to focus at different points and the image of a point object is on a point Which of the following statements are correct regarding spherical aberration :
physics-General
physics-
Spherical aberration in spherical mirrors is a defect which is due to dependence of focal length ‘f’ on angle of incidence ‘ q ’ as shown in figure is given by where R is radius of curvature of mirror and q is the angle of incidence The rays which are closed to principal axis are called paraxial rays and the rays far away from principal axis are called marginal rays As a result of above dependence different rays are brought to focus at different points and the image of a point object is on a point For paraxial rays, focal length approximately is
Spherical aberration in spherical mirrors is a defect which is due to dependence of focal length ‘f’ on angle of incidence ‘ q ’ as shown in figure is given by where R is radius of curvature of mirror and q is the angle of incidence The rays which are closed to principal axis are called paraxial rays and the rays far away from principal axis are called marginal rays As a result of above dependence different rays are brought to focus at different points and the image of a point object is on a point For paraxial rays, focal length approximately is
physics-General
physics-
Spherical aberration in spherical mirrors is a defect which is due to dependence of focal length ‘f’ on angle of incidence ‘ q ’ as shown in figure is given by where R is radius of curvature of mirror and q is the angle of incidence The rays which are closed to principal axis are called paraxial rays and the rays far away from principal axis are called marginal rays As a result of above dependence different rays are brought to focus at different points and the image of a point object is on a point The total deviation suffered by the ray falling on mirror at an angle of incidence equal to 60° is
Spherical aberration in spherical mirrors is a defect which is due to dependence of focal length ‘f’ on angle of incidence ‘ q ’ as shown in figure is given by where R is radius of curvature of mirror and q is the angle of incidence The rays which are closed to principal axis are called paraxial rays and the rays far away from principal axis are called marginal rays As a result of above dependence different rays are brought to focus at different points and the image of a point object is on a point The total deviation suffered by the ray falling on mirror at an angle of incidence equal to 60° is
physics-General
physics-
Spherical aberration in spherical mirrors is a defect which is due to dependence of focal length ‘f’ on angle of incidence ‘ q ’ as shown in figure is given by where R is radius of curvature of mirror and q is the angle of incidence The rays which are closed to principal axis are called paraxial rays and the rays far away from principal axis are called marginal rays As a result of above dependence different rays are brought to focus at different points and the image of a point object is on a point If fp and fm represent the focal length of paraxial and marginal rays respectively, then correct relationship is :
Spherical aberration in spherical mirrors is a defect which is due to dependence of focal length ‘f’ on angle of incidence ‘ q ’ as shown in figure is given by where R is radius of curvature of mirror and q is the angle of incidence The rays which are closed to principal axis are called paraxial rays and the rays far away from principal axis are called marginal rays As a result of above dependence different rays are brought to focus at different points and the image of a point object is on a point If fp and fm represent the focal length of paraxial and marginal rays respectively, then correct relationship is :
physics-General
physics-
Most materials have the refractive index, n > 1 So, when a light ray from air enters a naturally occurring material, then by Snell’s 
it is understood that the refracted ray bends towards the normal But it never emerges on the same side of the normal as the incident ray According to electromagnetism, the refractive index of the medium is given by the relation, 
, where c is the speed of the electromagnetic waves in vacuum, v its speed in the medium, er and mr are negative, one must choose the negative root of n Such negative refractive index materials can now be artificially prepared and are called metamaterials They exhibit signficantly different optical behaviour, without violating any physical laws Since n is negative, it results in a change in the direction of propagation of the refracted light However, similar to normal materials, the frequency of light remains unchanged upon refraction even in metamaterials For light incident from air on a meta-material, the appropriate ray diagrams
Most materials have the refractive index, n > 1 So, when a light ray from air enters a naturally occurring material, then by Snell’s it is understood that the refracted ray bends towards the normal But it never emerges on the same side of the normal as the incident ray According to electromagnetism, the refractive index of the medium is given by the relation, , where c is the speed of the electromagnetic waves in vacuum, v its speed in the medium, er and mr are negative, one must choose the negative root of n Such negative refractive index materials can now be artificially prepared and are called metamaterials They exhibit signficantly different optical behaviour, without violating any physical laws Since n is negative, it results in a change in the direction of propagation of the refracted light However, similar to normal materials, the frequency of light remains unchanged upon refraction even in metamaterials For light incident from air on a meta-material, the appropriate ray diagrams
physics-General
maths-
The element in the first row and third column of the inverse of the matrix 
is
The element in the first row and third column of the inverse of the matrix is
maths-General
maths-
If A and B are non-singular square matrices of same order, then 
is equal to
If A and B are non-singular square matrices of same order, then is equal to
maths-General
maths-
If d is the determinant of a square matrix A of order n, then the determinant of its adjoint is
If d is the determinant of a square matrix A of order n, then the determinant of its adjoint is
maths-General
chemistry-
In the above sequence X can be
In the above sequence X can be
chemistry-General
physics-
A ray of light traveling in air is incident at grazing angle (Ð >i 90º) on a long rectangular slab of a transparent medium of thickness t = 1.0 m The point of incidence is the medium A (0, 0) The medium has a variable index of refraction n(y) given by 
where 
The refractive index of air is 1 The coordinates (x1, y(A) of the point P where the ray intersects the upper surface of the slabair boundary are
A ray of light traveling in air is incident at grazing angle (Ð >i 90º) on a long rectangular slab of a transparent medium of thickness t = 1.0 m The point of incidence is the medium A (0, 0) The medium has a variable index of refraction n(y) given by where The refractive index of air is 1 The coordinates (x1, y(A) of the point P where the ray intersects the upper surface of the slabair boundary are
physics-General
physics-
A ray of light traveling in air is incident at grazing angle (Ð >i 90º) on a long rectangular slab of a transparent medium of thickness t = 1.0 m The point of incidence is the medium A (0, 0) The medium has a variable index of refraction n(y) given by where The refractive index of air is 1 Equation for the trajectory y(x) of the ray in the medium is
A ray of light traveling in air is incident at grazing angle (Ð >i 90º) on a long rectangular slab of a transparent medium of thickness t = 1.0 m The point of incidence is the medium A (0, 0) The medium has a variable index of refraction n(y) given by where The refractive index of air is 1 Equation for the trajectory y(x) of the ray in the medium is
physics-General
physics-
A ray of light traveling in air is incident at grazing angle (Ð >i 90º) on a long rectangular slab of a transparent medium of thickness t = 1.0 m The point of incidence is the medium A (0, 0) The medium has a variable index of refraction n(y) given by where The refractive index of air is 1 The incident angle at B(x, y) in the medium and the slope at B are related by the formula
A ray of light traveling in air is incident at grazing angle (Ð >i 90º) on a long rectangular slab of a transparent medium of thickness t = 1.0 m The point of incidence is the medium A (0, 0) The medium has a variable index of refraction n(y) given by where The refractive index of air is 1 The incident angle at B(x, y) in the medium and the slope at B are related by the formula
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A point object ‘O’ is placed along x-axis An equi-convex thin lens 
of focal length f=20cm in air is placed so that its principal axis is along x-axis Now the lens is cut at the middle (along the principal axis) and upper half is shifted along x-axis and y-axis by 20cm and 2mm respectively and right side of lower half is filled with water 
co-ordinates of image formed by lenses are
A point object ‘O’ is placed along x-axis An equi-convex thin lens of focal length f=20cm in air is placed so that its principal axis is along x-axis Now the lens is cut at the middle (along the principal axis) and upper half is shifted along x-axis and y-axis by 20cm and 2mm respectively and right side of lower half is filled with water co-ordinates of image formed by lenses are
physics-General
