Mass length & Time Measurements

1. The order of magnitude of mass of Electron

• 30
• 27
• 26
• none of these

2. To measure the distance of the planet from the earth ______ method is used

• Echo
• direct
• parallax
• none of these

3. When Planet Jupiter is at a distance of 824.7million km from earth , its angular diameter is measured to be 35.72’’ of arc , calculate diameter of Jupiter

• 1.429x10 8 m
• 1.429x10 7 m
• 2.429x10 8 m
• 1.429x10 11 m

4. RADAR stands for

• Radio detection and revise
• Radio detection and ranging
• Range detection and radio
• none of these

5. A radar signal is beamed towards a planet and its echo received 7min later, if the distance between the planet and earth is 6.3x10 10 m , calculate the speed of signal

• 4x10 8 m/s
• 3x10 8 m/s
• 9x10 8 m/s
• 12x10 8 m/s

6. The parallax of heavenly body measured from two points diametrically opposite on equator of earth is 1.0minute , if the radius of earth is 6400km , find the distance of heavenly body from the centre of earth in AU ( 1.AU =1.496x1011 m )

• 0.293 AU
• 0.493 AU
• 0.693AU
• 0.893AU

7. The order of magnitude of Universal gravitational constant

• -40
• -30
• -20
• -10

8. Find the height of tower if the angle of elevation of its top increases from 30 degree to 45 degree on moving 100m towards the tower in horizontal direction through base of tower

• 105.6m
• 116.6m
• 136.6m
• 150m

9. The moon is observed from two diametrically opposite points A and B on earth The angle θ subtended at the moon by two directions of observation is 10 54’ , Given the diameter of earth is about 1.276x10 7 m , calculate the distance of moon from earth

• 7.48x10 8 m
• 3.48x10 9 m
• 4.48x108 m
• 3.48x10 8 m

10. Find the angle of elevation of the sun, when the length of the shadow of a tree is equal to the height of the tree, is:

• 60 degree
• 45 degree
• 90 degree
• 30 degree