Speed of light in vacuum is:
Speed of light in a vacuum is 3 x 108 m/s The speed of light in a vacuum is 186,... View Article
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How far away is the cliff from the child, if a child hears an echo from a cliff 6 second after the sound produced by powerful horn? The velocity sound in air at 22oC is 344 m/s.
Let the distance between cliff and child be d m. Then, total distance traveled by the sound = 2d, Total time... View Article
A ray of light passing through the centre of curvature of a spherical mirror, after reflection passes through
A ray of light passing through centre of curvature of a spherical mirror is reflected back along the same path,... View Article
The size of the image formed by the convex mirror is
The size of the image formed by the convex mirror is always smaller than the size of the object irrespective... View Article
The magnification of a convex mirror is always:
The image formed by a convex mirror is always smaller in size than the object; hence its magnification is less... View Article
An electron traveling north enters a region where the electric field is uniform and points North. The electron:
We know that an electron is negatively charged and force is always opposite to the direction of electric field. So... View Article
The centripetal force on a satellite revolving around the earth is F. The gravitational force of the earth is also F. The net force on the satellite is:
Here, the gravitational force acts as a centripetal force. The gravitational force provides the necessary centripetal force.
Linear momentum is given by:
Linear momentum is the product of mass and linear velocity. What is Linear momentum? Momentum is directly proportional to the... View Article
The concave mirrors are used in
The concave mirrors are used in reflecting telescopes as parabolic mirrors, in magic lanterns, and in cinema projectors etc. Explanation... View Article
The mirror used as rear view mirror is
Convex mirrors have very wide field of view as they are curved outwards. So, the convex mirrors enable the driver... View Article
A stone weighing 1 kg is dropped from rest from a height of 4 metres above the ground. When it has free-fallen 1 metre its total energy with respect to the ground is
Energy is conserved in free-fall situations (no external forces doing work). Thus, the total energy would be the same at... View Article
How much energy does a 150 W steam iron consume per second?
Power of the steam iron = 150 w Time= 1 sec Energy consumed by iron = P x t =... View Article
Harry is standing in front of a plane mirror at a distance of 6 m. His image on the other side will form at a distance of
For reflection through a plane mirror, Image distance (v) = Object distance (u) = 6 m
Angle of reflection is
Angle of reflection is the angle formed between the reflected ray and the normal.
Is the lateral inversion of
The mirror image of is REFLECTION.
Find the work done
The kinetic energy of a body changes from 12 J to 60 J due to the action of a force... View Article
A ball is thrown vertically upward with a velocity of 60 m/s. The maximum height to which ball rises is
u = 60 m/s, v = 0. The value of acceleration due to gravity is g = 9.8 m/s2 From... View Article
The force of gravitation between two bodies varies with r as:
F = Gm1m2/r2. Thus, F is inversely proportional to r2.
A ball is thrown vertically upwards with a velocity ‘u’. The velocity with which it falls to the earth again is:
For vertically upward motion: g is negative as it opposes the motion. v = u – gt 0 = u... View Article
There is some water in the beaker placed on the pan of a spring balance. If we dip our finger in the water without touching the bottom of the beaker, then what is the change in the reading of spring balance?
When we dip our finger in the water, the water exerts upward thrust on the finger (Archimedes’s principle). Due to... View Article
