revision grade 9 u 1/2

The time is one of -------------physical quantities.

The real image is not formed by using ---------- mirror or plane mirror.

The vision defect which is due to the decrease of convexity of the eye lens surface is called -----------------

If the object at rest moves regularly until its speed reaches 12 m/sec. after 3 seconds, so its acceleration equals ------------

scientific term:

The distance between the focus of the concave mirror and its pole

sc. term :

A disease that causes a difficulty of vision as a result of the darkness of the eye lens.

The two factors which can be used to describe the motion of a body are the

a speed and time.

b. distance and time.

c. area and time.

d. displacement and speed.

The relative speed of a moving object relative to an observer moves at the same speed in the opposite direction is -----------

a. double

b. the same.

c. half.

d quarter

Correct the underlined words

1. If the angle between the incident ray and the surface of the plane mirror equals 90°, so the angle of reflection equals to 45

Correct the underlined words

If a light ray falls passing through the optical center of the convex lens, it exists

passing through the focus