Q1.When a c
oncave mirror is placed facing the Sun, the Sun’s rays converge to a point
10 cm from the mirror.
Now, if you place a 2 cm long candles flame 20 cm away on
the principal axis of the mirror, where would you place a screen to obtain the image
of the candle? What would see the size of the image? Draw a ray diagram to justify
your answer.
Q2.A student has to project a three times magnified image of a candle flame on a wa ll. Name the type of the lens (c onverging/ diverging) required for the purpose. It the candle flame is at a distance of 6 m from the wall, find the focal length of the lens.
. Q3. A child while playing with his father’s spectacles burnt a hole in a piece of them tissue paper by focusing the image of the Sun on at.
a) Name the defect of vision his father is suffering form.
b) List two causes of the defect.
c) Draw a ray diagram to show how this defect may be corrected using a suitable lens.
Q4.A. Explain the formation of rainbow in the sky with the help of a diagram. List the three phenomena of light involved. Which colour – violet or red appears at top of the rainbow?
B. What is the difference in colours of the sun observed during sunrise/sunset and noon? Give e xplanation for each.
Q5.(i) Which property of concave mirror is utilized for using them as shaving mirrors?
(ii) Light passes through a rectangular glass slab and through a triangular glass prism. Using proper ray diagram, explain in what way does the direction of the two emergent beams differs with respect to the incident beam of light.
(iii) A concave lens has a focal length of 50 cm Calculate its power
Q6.(i) Rohit claims to have obtained an image twice the size of object with a concave lens. Is he correct? Give reason for your answer.
(ii) Where should an object be placed in case of a convex lens to form an image of same size as of the object? Show with the help of ray diagram the position and the nature of the image formed.
(iii) With the help of ray diagram, illustrate the change in position, nature and size of the image formed if the convex lens in case of (ii) is replaced by concave lens of same focal length
Q7.(i)What is persistence of vision? How do we make a mot ion picture possible?
(ii)What is power of lens?Define 1 Dioptre
(iii)A lens has power of +3d find its focal length
Q8.(i) Define: (a) Centre of curvature (b) Pole of a concave mirror (c)Principle Axis
Q9.Give some points of similarities and dissimilaritie s between a camera and a human eye.
Q10.(i).With respect to air, the refractive index of ice is 1.31 and that of rock salt is 1.54. Calculate the refractive index of rock salt with respect to ice.
(ii) State Snell’s law of reflection of light.
(iii) A transparent medium A floats on another trans parent medium B. When a ray of light travels obliquely from A into B, the reflected ray bends away from the normal. Which of the two media A and B if optically denser and why?
Q11What are optical fibres? Give three applications of these fibres.
Q12.Sheeba studies in grade 9 and is a secretary of sch ool’s club. As per practice in the school, all members of science club assemble in Physics lab in last two periods on every Friday. Sheeba also extends help to her mother in kitchen. One day she observed that the apparent random wavering or flickering of objects seen throu gh a turbulent stream of hot air rising above the fire in the kitchen. She discussed about this with her friends and decided to raise the question in school’s science club meeting. Read the given passage and answer the following que stions:
(a) Explain the reason behind the observation.
(b) Name the similar phenomenon on a larger scale. Also , draw the ray diagram.
(c) What values are shown by Sheeba?
Q2.A student has to project a three times magnified image of a candle flame on a wa ll. Name the type of the lens (c onverging/ diverging) required for the purpose. It the candle flame is at a distance of 6 m from the wall, find the focal length of the lens.
. Q3. A child while playing with his father’s spectacles burnt a hole in a piece of them tissue paper by focusing the image of the Sun on at.
a) Name the defect of vision his father is suffering form.
b) List two causes of the defect.
c) Draw a ray diagram to show how this defect may be corrected using a suitable lens.
Q4.A. Explain the formation of rainbow in the sky with the help of a diagram. List the three phenomena of light involved. Which colour – violet or red appears at top of the rainbow?
B. What is the difference in colours of the sun observed during sunrise/sunset and noon? Give e xplanation for each.
Q5.(i) Which property of concave mirror is utilized for using them as shaving mirrors?
(ii) Light passes through a rectangular glass slab and through a triangular glass prism. Using proper ray diagram, explain in what way does the direction of the two emergent beams differs with respect to the incident beam of light.
(iii) A concave lens has a focal length of 50 cm Calculate its power
Q6.(i) Rohit claims to have obtained an image twice the size of object with a concave lens. Is he correct? Give reason for your answer.
(ii) Where should an object be placed in case of a convex lens to form an image of same size as of the object? Show with the help of ray diagram the position and the nature of the image formed.
(iii) With the help of ray diagram, illustrate the change in position, nature and size of the image formed if the convex lens in case of (ii) is replaced by concave lens of same focal length
Q7.(i)What is persistence of vision? How do we make a mot ion picture possible?
(ii)What is power of lens?Define 1 Dioptre
(iii)A lens has power of +3d find its focal length
Q8.(i) Define: (a) Centre of curvature (b) Pole of a concave mirror (c)Principle Axis
Q9.Give some points of similarities and dissimilaritie s between a camera and a human eye.
Q10.(i).With respect to air, the refractive index of ice is 1.31 and that of rock salt is 1.54. Calculate the refractive index of rock salt with respect to ice.
(ii) State Snell’s law of reflection of light.
(iii) A transparent medium A floats on another trans parent medium B. When a ray of light travels obliquely from A into B, the reflected ray bends away from the normal. Which of the two media A and B if optically denser and why?
Q11What are optical fibres? Give three applications of these fibres.
Q12.Sheeba studies in grade 9 and is a secretary of sch ool’s club. As per practice in the school, all members of science club assemble in Physics lab in last two periods on every Friday. Sheeba also extends help to her mother in kitchen. One day she observed that the apparent random wavering or flickering of objects seen throu gh a turbulent stream of hot air rising above the fire in the kitchen. She discussed about this with her friends and decided to raise the question in school’s science club meeting. Read the given passage and answer the following que stions:
(a) Explain the reason behind the observation.
(b) Name the similar phenomenon on a larger scale. Also , draw the ray diagram.
(c) What values are shown by Sheeba?
No comments:
Post a Comment