REFLECTION
Q1: Explain why a ray of light passing through the centre of curvature of a concave mirror gets reflected along the same path.
Q2: What is the nature of image formed by a concave mirror if the magnification produced by the mirror is +3?
Q3: Write two different uses of concave mirrors.
Q4: An object is kept at a distance of 4m in front of a special mirror which forms its erect image at a distance of 1.0 m from the mirror. What is the magnification? Is the mirror concave or convex?
Q5: A ray of light LM is incident on a mirror as shown in the figure. The angle of incidence for this ray is the angle between it and the line joining two other points in the figure. Name these two points.
REFRACTION
Q6: Why does a ray of light bend when it travels from one medium into another?
Q7: Name the component of white light that has the greatest wavelength.
Q8: How should a ray of light be incident on a rectangular glass slab so that it comes out from the opposite side of the slab without being displaced?
Q9: The following table gives the values of refractive indices of few media.
| S.No. | 1 | 2 | 3 | 4 | 5 |
| Medium | Water | Crown Glass | Rock Salt | Ruby | Diamond |
| Refractive Index | 1.33 | 1.52 | 1.54 | 1.71 | 2.42 |
Use this table to give an example of a medium pair so that light speeds up when it goes from one of these media to another.
Q10: Draw the given diagram in your answer book and complete it for the path of ray of light beyond the lens.
Q11: A girl was playing with a thin beam of light from her laser torch by direction it from different directions on a convex lens held vertically. She was surprised to see that in a particular direction the beam of light continues to move along the same direction through the lens. State the reason for this observation.
Q12: Define power of a lens.
HUMAN EYE
Q13: Name the part of our eyes that helps us to focus near and distant objects in quick succession.
NATURAL PHENOMENA
Q14: Why does sky look blue on a clear day?
Q15: List the three phenomena of light responsible for formation of rainbow in the sky?
Q16: Why do we see stars twinkling whereas, planets do not twinkle?
ELECTRICITY
Q17: Generally, alloys are used in electrical heating devices instead of pure metals. What could be the reason?
MAGNETISM
Q18: A charged particle enters at right angles into a uniform magnetic field as shown. What should be the nature of charge on the particle if it begins to move in a direction pointing vertically out of the page due to its interaction with the magnetic field?
Answers
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