Important Question with solution
Q1: Does the flame of a gas stove emit light?
Ans: Yes.
Q2: What is rectilinear propagation of light?
Ans: Light travels in a straight line.
Q3: Write the names of 4 different sources of light?
Ans: Bulb, sun, stars, firefly
Q4: Give one example of living thing which emits light?
Ans: Jugnu {firefly)
Q5: Sometimes you are able to see sun or moon behind the clouds .What can you say about the ability of such clouds to transmit light?
Ans: Yes, clouds transmit light.
Q6: Image formed in a pinhole camera is inverted .Why?
Ans: It is inverted because of the rectilinear propagation of light.
Q7: Can you suggest the shape of the shadows?
Ans: It is usually similar to the object.
Q8: Does the length of shadow change from season to season?
Ans: Yes if observed at same time .
Q9: Define reflection of light?
Ans: The process of returning/ bouncing back the light to the same medium after Striking a surface is called reflection of light.
Q10: What is a reflector?
Ans: A surface which reflects the light is called reflector.
Q11: What is shadow?
Ans: A dark patch formed behind an opaque object when it is placed in the path of light is called shadow.
Q12: What do you mean by reflection of light?
Ans:Coming back of light ray incident on a surface is called reflection.
Q13: What is the principle of working f a pin hole camera?
Ans: A pinhole camera is based on rectilinear propagation of light?
Q14: Can light pass through opaque objects?
Ans: No
Q15: What is an artificial source of light?
Ans: Man made sources of light. For example: electric bulb, candle etc.
Q16: Classify the following into transparent, translucent, and opaque objects.
Glass, air, oil, oily paper, rubber sheet, polythine, water, football, table
Ans:
Transparent: air, glass, water
Translucent: oil, oily paper, polythine
Opaque: rubber sheet, football, table
Q17: Name two artificial sources of light?
Ans: Electric bulb, candle
Q18: Name one transparent and one opaque body?
Ans: Transparent: air Opaque: stone
Q19: Give one example of most commonly used reflector?
Ans: Looking glass or plane mirror
Q20: Does the reflection of light from the surface similar to the bouncing back of a rubber ball after it strikes from a ball? Explain.
Ans: Yes, because of reflection, light falling on a surface bounces back to the same medium. When a light strikes a surface after the reflection it turns back in the same medium.
Q22: Give the properties of the image formed by the plane mirror?
Ans: The basic properties of plane mirror is as follow;
(i) The plane mirror alsways forms a virtual and errect image.
(ii) Size of the image formed by plane mirror is equal to the size of the object.
