# KVPY (Kishore Vaigyanik Protsahan Yojana) Stream SB-SX (Class 12 & 1st Year B.Sc.) Physics: Questions 60 - 62 of 268

Get 1 year subscription: Access detailed explanations (illustrated with images and videos) to 268 questions. Access all new questions we will add tracking exam-pattern and syllabus changes. View Sample Explanation or View Features.

Rs. 200.00 or

## Question number: 60

Appeared in Year: 2012

MCQ▾

### Question

In one model of the election, the mass of electron me is thought to be a uniformly charged shell of radius R and total charge e, whose electrostatic energy E is equivalent to its mass me via Einstein’s mass energy relation E = mec2. In this model, R is approximately – (me = 9.1 × 10-31kg, c = 3 × 108 ms-1, magnitude of the electron charge = 1.6 × 10-19 C)

### Choices

Choice (4) Response

a.

b.

c.

d.

## Question number: 61

Appeared in Year: 2011

MCQ▾

### Question

At a distance l from a uniformly charged long wire, a charged particle is thrown radially outward with a velocity u in the direction perpendicular to the wire. When the particle reaches a distance 2l from the wire its speed is found to be. The magnitude of the velocity, when it is a distance 4l away from the wire, is (ignore gravity)

### Choices

Choice (4) Response

a.

b.

c.

d.

## Question number: 62

Appeared in Year: 2012

MCQ▾

### Question

A conducting rod of mass m and length l is free to move without friction on two parallel long conducting rails, as shown below. There is a resistance R across the rails. In the entire space around, there is a uniform magnetic field B normal to the plane of the rod and rails. The rod is given an impulsive velocity v0.

Finally, the initial energy

### Choices

Choice (4) Response

a.

will be converted fully into magnetic energy due to induced current

b.

will enable rod to continue to move with velocity v0 since the rails are frictionless

c.

will be converted fully into heat energy in the resistor

d.

will be converted into the work done against the magnetic field

f Page