Physics Test 23...

A satellite is in a circular orbit very close to the surface of a planet. At some point it is given an impulse along its direction of motion, causing its velocity to increase η times. It now goes into an elliptical orbit, with the planet at the centre of the ellipse. The maximum possible value of η for this to occur is

A conductor lies along the z-axis at -1.5 ≤ z < 1.5 m and carries a fixed current of  find the power required to move the conductor at constant speed to x = 2.0 m, y = 0 m in 5 × 10^–3 s. Assume parallel motion along the x-axis.

N identical cells, each of emf  ε and internal resistance r, are joined in series. Out of these, n cells are wrongly connected, i.e. their terminals are connected in reverse of that required for series connection. n < (N/2). Let  ε₀ be the emf of the resulting battery and r₀ be its internal resistance.

A skier plans to ski a smooth fixed hemisphere of radius R. He starts from rest from a curved smooth surface of height (R/4). The angle θ at which he leaves the hemisphere is

In a region of space, a uniform magnetic field B exists in the y - direction. A proton is fired from the origin, with its initial velocity v making a small angle α with the y-direction in the yz plane. In the subsequent motion of the proton,

A thread is tied slightly loose to a wire frame as in figure and the frame is dipped into a soap solution and taken out. The frame is completely covered with the film. When the portion A is punctured with a pin, the thread 

A capacitor is charged and then made to discharge through a resistance. The time constant is τ. In what time will the potential difference across the capacitor decrease by 10%.

In an npn transistor circuit, the collector current is 10mA. If 95 per cent of the electrons emitted reach the collector, which of the following statements are true?

A closed coil having 50 turns, area 300 cm², is rotated from a position where its plane makes an angle of 45º with a magnetic field 2.0 Tesla to a position perpendicular to the field in a time of 0.1 sec. The average e.m.f. induced in the coil is

If the electric potential of the inner metal sphere is 10 volt & that of the outer shell is 5 volt, then the potential at the centre will be :