Physics Test - ...

A simple pendulum whose length is slightly less than that of a seconds pendulum start vibrating with another seconds pendulum in the same phase. After 22 seconds, they again vibrate in the same phase. The periodic time of simple pendulum is-

If the radius of Earth decreases by \(1\%\) and its mass remains the same, then the acceleration due to gravity:

If the radius of Earth suddenly decreases to \(80 \%\) of its present value (the mass of Earth remaining the same), then the value of acceleration due to gravity will:

If a person goes to a depth equal to the radius of Earth below its surface, then what would be his weight relative to that on Earth?

In Nehru Planetarium, an astronomical telescope which has an objective lens of diameter 10 m. To see anything through this telescope, planetarium team glow a light of wavelength 7000Α°. What will be the resolving power of this telescope?

For a lens of simple microscope, with magnifying power 2, what is the minimum value of distance for clear vision if the focal length of the lens is 20 m?

Two balls are projected simultaneously in the same vertical plane from the same point with velocities \(V _{1}\) and \(V _{2}\) at angles \(\theta_{1}\) and \(\theta_{2}\), respectively, with the horizontal. If \(V _{1} \cos \theta_{1}= V _{2} \cos \theta_{2}\), the path of one ball as seen from the position of other ball is:

A body is projected at time \(t=0\) from a certain point on a planet's surface with a certain velocity at a certain angle with the planet's surface (assumed horizontal). The horizontal and vertical displacements \(x\) and \(y\) (in metres) respectively vary with time \(t\) (in seconds) as: \(x=10 \sqrt{3} t\) and \(y=10 t-t^{2}\)

What is the magnitude and direction of the velocity with which the body is projected?