One lumen _____ candle power.
Important Questions on Light
(A) Check whether the image formed is virtual or real.
(B) Check whether the virtual image formed is dimished, magnified or same size as that of the object.
(C) If the image formed is real, the mirror used is concave.
(D) If a magnified virtual image is formed, the mirror is concave; if a diminished virtual image is formed, the mirror is convex and if the size of the image is equal to the size of the object, plane mirror is used.
Write the following steps in sequential order to verify the laws of reflection.
(A) Draw a normal at the point where the two lines PQ and P₁ Q1 meet.
(B) Remove the pins and the mirror and join P, Q similarly join P 1,Q1-
(C) View the image of P and Q and fix two more pins P₁ and Q₁ such that the images of pins P, Q and P1, Q₁ are along the same line.
(D) Draw a straight line on a white paper spread on the table and fix a plane mirror on the line.
(E) Fix two pins P and Q in front of the mirror.
(F) Measure the angle of incidence and angle of reflection and compare them to verify the law reflection.
A ray of light is incident on a plane mirror, making an angle 'q' with the surface of the mirror. Arrange the following steps in sequential order to calculate the angle between the incident light ray and the reflected light ray.
(A) Draw a normal line on the plane mirror at the point of incidence of the light ray.
(B) Note down the angle between the plane mirror and the incident light ray.
(C) The sum of the angle of incidence and the angle between the plane mirror and the incident ray is 90°. Determine the angle of incidence.
(D) From the laws of reflection, the angle of incidence is equal to the angle of reflection. Then the sum of the angle of incidence and the angle of reflection gives the angle between the incident light ray and the reflected light ray.
(A) Draw two incident light rays, one parallel to the principal axis and the other coming from the centre of curvature and draw the paths of the reflected light rays.
(B) The reflected light rays are diverging. So, draw the extended lines till they intersect.
(C) Draw a concave mirror and mark the pole, the principal focus, and the centre of curvature of the mirror.
(D) Mark the image at the point of intersection of the extended light rays and write the nature of the image.
(E) Draw the principal axis and mark the position of the object on the principal axis between the pole and the principal focus.
