Page 166 - Physics_Form_2
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Physics for Secondary Schools
Parabolic solar cookers: These solar 3. An object is 15 cm in front of a
cookers convert sunlight directly into heat diverging mirror. What is the focal
by concentrating it through a parabolic length of the mirror if a virtual image
arrangement of reflectors. Figure 4.42 is formed 10 cm behind the mirror?
shows a parabolic solar cooker. 4. A 4 cm tall object is placed 10 cm
from a concave mirror with a radius
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of curvature of 12 cm. Determine
the focal length of the mirror, image
distance, image height, and nature of
the image.
5. An object is placed 30 cm in front of
a concave mirror with a 15 cm focal
length. Determine the image distance
and magnification. Is the image real
or virtual, upright or inverted?
Figure 4.42: A parabolic solar cooker 6. Name any three real life uses for each
of the concave and convex mirrors.
Project 4.2 Chapter summary
1. Light is a form of energy that is
Design and construct a simple solar visible to the human eye and enables
cooker using a concave mirror or a the perception of objects.
parabolic reflector. Utilise materials 2. Propagation of light is the passage of
such as cardboard, aluminium foil, and light through different media, which
a transparent cover. Test the cooker by can involve reflection, refraction,
attempting to heat or cook food items and absorption.
with sunlight. Document the process, 3. A plane mirror is a flat, reflective
results, and any challenges encountered. surface that creates virtual images
of objects.
Exercise 4.3 4. Laws of Reflection:
(a) The angle of incidence equals
1. Why do concave mirrors produce the angle of reflection.
both real and virtual images, but (b) Incident rays, reflected rays, and
convex mirrors produce only virtual the normal line lie in the same
images? plane
2. A nail of 6 cm in height is placed 5. A curved mirror has a curved surface,
30 cm from a converging mirror of
focal length 10 cm. Determine the which can be concave or convex.
position and height of the image. A concave mirror is a mirror that
State also whether the image is real curves inward, capable of focusing
or virtual, enlarged or diminished. light and producing enlarged images.
160
Student’s Book Form Two
Physics Form 2 Final.indd 160 25/10/2025 10:27
