Immediately after the end of a total solar eclipse, the so-called ‘diamond ring’ is observed. This is due to
The rays winking through the mountains on the moon
The rays passing through the irregularities in the rim of the solar disc
The irregular refraction of the dying sunlight through the solar atmosphere
The irregular refraction of the dying sunlight through the earth’s atmosphere
In the case of motors and lorries moving along a bend, the centripetal force is provided by
The gravitational attraction between the motors/lorries and the earth
The friction between the roads and the tyres of the wheels
The reaction of the ground on the motor/ lorry
Kinetic energy of motor or lorry
In the S.I. system, a mole is a unit of
Molecular mass
Molecular size
Mean free path
Amount of a substance in a system
A moving body of mass m and velocity 3 kmh-1 collides with a body at rest of mass 2 m and sticks to it. Now the combined mass starts to move. What will be the combined velocity?
3 kmh-1
2 kmh-1
1 kmh-1
4 kmh-1
In which atmospheric layer are the communication satellites located?
Stratosphere
Ionosphere
Troposphere
Exosphere
A ball is dropped from a spacecraft revolving around the earth at a height of 120 km. What will happen to the ball?
It will continue to move with velocity v along the original orbit of spacecraft
It will move with the same speed tangentially to the spacecraft
It will fall down to the earth gradually
It will go very fair in the space
Two boats are moving in same direction in a river. What is the best condition so that they more parallel in the same direction?
Both move away from each other
They are slightly bent towards each other
They are parallel to each other
It is not possible
A cylinder contains 2L of nitrogen at 20oC and 15 atm. What will be the final pressure of ideal gas if the temperature is raised to 35oC and volume is reduced to 4L?
7.8 atms
8 atms
6 atm
7.5 atm
The efficiency of an autmobile engine is 20% and it operates at 90 cycle per second. If it work at the rate of 120 hp, how much heat does the engine absorb per cycle?
4973 J
4450 J
4282 J
4000 J
What will be the work done by the refrigerator if the refrigerator has coefficient of performance = 4 and extracts heat from cold chamber at a rate of 252J per cycle?
-63 J
+63 J
-53 J
+53 J