If the angular diameter of the moon be 30, how far from the eye a coin of diameter `2. 2c m` be kept to hide the moon?

An iron tyre of diameter 2 m is to be fitted on to a wooden wheel of diameter 2.01 m. The temperature to which the tyre must be heated , if alpha=11xx10^(-6).^@C^(-1) and room temperature is 20^@C , will be

Find the diameter of the image of the moon formed by a spherical concave mirror of focal length 7.6 m. The diameter of the moon is 3450 km and the distance of the earth and the moon is 3.8 xx 10^5 km.

Assuming the distance of the earth from the moon to be 38,400 km and the angle subtended by the moon at the eye of a person on the earth to be 31’, find the diameter of the moon.

Assuming the distance of the earth from the moon to be 38,400 km and the angle subtended by the moon at the eye of a person on the earth to be 31, find the diameter of the moon.

A giant telescope in an observatory has an objective of focal length 19 m and an eye-piece of focal length 1.0 cm . In normal adjustment, the telescope is used to view the moon. What is the diameter of the image of the moon formed by the objective? The diameter of the moon is 3.5 xx 10^(6)m . and the radius of the lunar orbit round the earth is 3.8 xx 10^(8) m .

Find the distance from the eye at which a coin of 2 cm diameter should be held so as to conceal the full moon whose angular diameter is 31'.

The diameter of the moon is 3.5xx10^(3)km and its distance from the earth is 3.8xx10^(5) km . It is seen by a telescope having the focal length of the objective and the eye-piece as 4m and 10cm respectively. The diameter of the image of the moon will be approximately

The diameter of the moon is 3.5xx10^(3)km and its distance from the earth is 3.8xx10^(5) km . It is seen by a telescope having the focal length of the objective and the eye-piece as 4m and 10cm respectively. The diameter of the image of the moon will be approximately

Determine the diameter of the image formed by a spherical concave mirror of focal length 8 m. The diameter of the moon is 3450 km and the distance between the earth and the moon is approx 4xx10^(5) km.

The diameter of the eye ball of a normal eye is about 2.5cm. The power of the eye lens varies from