Light chapter

The laws of reflection hold true for

• Plane mirror only

• all reflecting surface

• convex mirrors only

• Concave mirror only

When an object is kept within the focus of a concave mirror, an enlarged image is formed behind the mirror. This image is

• Real and inverted

• Virtual and erect

• Same size

• Diminished

The focal length of a plane mirror is

• 0

• Infinite

• -25 cm

• 25 cm

Where would the reflected rays meet for the image formation to take place?

The image shows the path of incident rays to a concave mirror.

• Behind the mirror

• Beyond C

• Between C and F

• Between F and O

A beam of light incident on a plane mirror forms a real image on reflection. The incident beam is:

• parallel

• not certain

• divergent

• convergent

A student conducts an experiment using a convex lens. He places the object at a distance of 60 cm in front of the lens and observes that the image is formed at a distance of 30 cm behind the lens. What is the power of the lens?

• 0.005 dioptre

• 0.05 dioptre

• 5 dioptre

• 50 dioptre

A student studies that the speed of light in air is 300000 km/sec, whereas that of speed in a glass slab is about 197000 km/sec. What causes the difference in the speed of light in these two media?

• Difference in density

• Difference in temperature

• Difference in the amount of light

• Difference in the direction of wind flow

A student conducts an activity using a concave mirror with a focal length of 10 cm. He placed the object 15 cm from the mirror. Where is the image likely to form?

• At 6 cm behind the mirror

• At 30 cm behind the mirror

• At 6 cm in front of the mirror

• At 30 cm in front of the mirror

Ali conducts an experiment using an object of height of 10 cm and a concave lens with a focal length of 20 cm. The object is placed at a distance of 25 cm from the lens. Can the image be formed on a screen?

• Yes, as the image formed will be real

• Yes, as the image formed will be erect

• No, as the image formed will be virtual

• No, as the image formed will be inverted

A 10 mm long awl pin is placed vertically in front pin is formed at 30cm in front of the mirror. The focal length of this mirror is:

• -30 cm

• -20 cm

• -40 cm

• -70 cm