Class 10 Light: Mirror Formula, Lens Formula and Power
- 1.
An object is placed 30 cm in front of a concave mirror of focal length 15 cm. Where is the image, and what is it like?
A30 cm in front of the mirror, real, inverted and the same sizeB15 cm in front of the mirror, real and diminishedC30 cm behind the mirror, virtual and erectDAt infinity - 2.
An object is placed 15 cm in front of a concave mirror of focal length 10 cm. What is the magnification of the image?
A+2B−0.5C−2D+0.5 - 3.
An object is placed 30 cm in front of a convex mirror of focal length 15 cm. Where is the image formed?
A10 cm in front of the mirrorB30 cm behind the mirrorC6 cm behind the mirrorD10 cm behind the mirror - 4.
A 5 cm tall object is placed in front of a concave mirror and the magnification is −3. Describe the image.
A15 cm tall, virtual and erectB1.7 cm tall, real and invertedC15 cm tall, real and invertedD3 cm tall, virtual and erect - 5.
An object is placed 15 cm from a convex lens of focal length 10 cm. Where is the image formed?
A6 cm from the lens on the same sideB30 cm from the lens on the other side, real and invertedC30 cm from the lens on the same side, virtual and erectD10 cm from the lens on the other side - 6.
An object is placed 10 cm from a convex lens of focal length 20 cm. Describe the image.
A20 cm from the lens on the other side, real and invertedB20 cm from the lens on the same side as the object, virtual, erect and twice the sizeC6.7 cm from the lens, diminishedDAt infinity - 7.
The table lists the power of four lenses. What is the focal length of lens B?
A5 cmB50 cmC20 cmD200 cm - 8.
A doctor prescribes a lens of power −2.5 D. What kind of lens is it, and what is its focal length?
AA convex lens of focal length 40 cmBA concave lens of focal length 25 cmCA convex lens of focal length 2.5 cmDA concave lens of focal length 40 cm - 9.
An object is placed 30 cm from a concave lens of focal length 15 cm. Where is the image formed?
A10 cm from the lens on the same side as the objectB30 cm from the lens on the other sideC10 cm from the lens on the other sideD15 cm from the lens on the same side - 10.
The table shows object and image distances measured in an experiment with a convex lens. What is the focal length of the lens?
A20 cmB15 cmC10 cmD5 cm
Class 10 Light: Mirror Formula, Lens Formula and Power — Answer key
- 1.A — 30 cm in front of the mirror, real, inverted and the same size2.C — −2
- 3.D — 10 cm behind the mirror4.C — 15 cm tall, real and inverted
- 5.B — 30 cm from the lens on the other side, real and inverted6.B — 20 cm from the lens on the same side as the object, virtual, erect and twice the size
- 7.C — 20 cm8.D — A concave lens of focal length 40 cm
- 9.A — 10 cm from the lens on the same side as the object10.C — 10 cm