Refraction Through a Lens Quiz - ICSE Class 10 Physics
Free practice quiz: Refraction Through a Lens (ICSE Class 10 Physics). 44 multiple-choice questions with answers and explanations. Play online, no sign-up needed.
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An object is placed at the center of curvature of a convex lens. Where will the image be formed?
- At the principal focus
- Beyond the center of curvature
- At the center of curvature
- Between the optical center and the principal focus
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Answer: C. At the center of curvature
When an object is placed at the center of curvature (2F) of a convex lens, the rays passing through the optical center go undeviated, and rays parallel to the principal axis pass through the principal focus after refraction. These refracted rays converge at the center of curvature on the other side of the lens. Therefore, the image is formed at the center of curvature, it is real, inverted, and of the same size.
An object is placed 50 cm from a convex lens of focal length 25 cm. The image formed is:
- Real, inverted, and diminished
- Virtual, erect, and magnified
- Real, inverted, and of the same size
- Real, inverted, and magnified
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Answer: C. Real, inverted, and of the same size
The object is placed at 50 cm from a convex lens with a focal length of 25 cm. This means the object is placed at 2F (twice the focal length), which is also the center of curvature. When an object is placed at 2F of a convex lens, the image formed is real, inverted, and of the same size, and it is also formed at 2F on the other side of the lens.
A concave lens diverges parallel rays of light. This means it is also known as a:
- Converging lens
- Focusing lens
- Diverging lens
- Magnifying lens
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Answer: C. Diverging lens
A concave lens causes parallel rays of light to spread out or diverge after passing through it. Therefore, it is called a diverging lens.
A beam of parallel light rays is incident on a convex lens. After refraction, the rays converge at:
- Infinity
- The optical center
- The principal focus
- A point beyond the principal focus
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Answer: C. The principal focus
By the definition of a convex lens, incident rays that are parallel to the principal axis converge at the principal focus (F) after refraction through the lens.
An object is placed at infinity in front of a concave lens. Where is the image formed?
- At the optical center
- At the principal focus
- At twice the focal length
- Beyond twice the focal length
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Answer: B. At the principal focus
When an object is placed at infinity in front of a concave lens, the rays incident on the lens are parallel. After refraction, these parallel rays diverge in such a way that they appear to originate from the principal focus (F) on the same side of the lens as the object. Thus, a virtual, erect, and highly diminished image is formed at the principal focus.