Shadow Formation — Homi Bhabha Class 9 Physics MCQs with Solutions
Free Homi Bhabha Class 9 Physics Shadow Formation MCQs with step-by-step solutions (8 questions). Part of Light & Optics. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Shadow Formation · medium · theory
Shadows are formed because light travels:
A. around obstacles
B. in curved paths
C. in straight lines (rectilinear propagation) ✓ Correct
D. faster through opaque objects
Solution: Since light travels in straight lines, an opaque object blocks it and casts a shadow.
Q2 — Shadow Formation · hard · theory
The dark central region of a shadow, where light is completely blocked, is called the:
A. umbra ✓ Correct
B. focus
C. aperture
D. penumbra
Solution: The umbra is the fully dark part; the lighter surrounding region is the penumbra.
Q3 — Shadow Formation · medium · theory
A solar eclipse occurs when:
A. the Sun comes between the Earth and the Moon
B. the Moon comes between the Sun and the Earth ✓ Correct
C. the Earth stops rotating
D. the Earth comes between the Sun and the Moon
Solution: In a solar eclipse the Moon's shadow falls on the Earth, blocking the Sun.
Q4 — Shadow Formation · medium · theory
A lunar eclipse occurs when:
A. the Moon comes between the Sun and the Earth
B. the Sun is blocked by a planet
C. the Earth comes between the Sun and the Moon ✓ Correct
D. the Moon enters the Sun
Solution: In a lunar eclipse the Earth's shadow falls on the Moon.
Q5 — Shadow Formation · hard · theory
A shadow is formed only by an object that is:
A. opaque ✓ Correct
B. translucent
C. transparent
D. luminous
Solution: Opaque objects block light and cast shadows; transparent objects let light pass through.
Q6 — Shadow Formation · easy · theory
Shadows are formed mainly because light travels:
A. In curved paths around objects
B. Only during the daytime
C. Faster through opaque objects
D. In straight lines ✓ Correct
Solution: Light travels in straight lines (rectilinear propagation). When an opaque object blocks these straight rays, the region behind it receives no light and a shadow forms.
Q7 — Shadow Formation · medium · theory
When an opaque object is lit by an extended source, the dark central region of the shadow where no light reaches at all is called the:
A. Corona
B. Penumbra
C. Umbra ✓ Correct
D. Aura
Solution: The fully dark inner part of a shadow, where light is completely blocked, is the umbra. The surrounding lighter, partially lit region is the penumbra.
Q8 — Shadow Formation · hard · numerical
At a certain time, a 2 m tall pole casts a 3 m long shadow. At the same moment, a nearby tree casts a 12 m long shadow. What is the height of the tree?
A. 8 m ✓ Correct
B. 18 m
C. 12 m
D. 6 m
Solution: Because the sun rays are parallel, the ratio of height to shadow length is the same for both objects: 2/3 = h/12, so h = (2 x 12)/3 = 8 m.