# JEE Physics paper for practice

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JEE Physic Paper set 3
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A paramagnetic sample shows a net magnetisation of 8 Am-1 when placed in an external magnetic field of 0.6 T at a temperature of 4K. When the same sample is placed in an external magnetic field of 0.2 T at a temperature of 16 K, the magnetisation will be

2

S is the surface of a lump of magnetic material.

3

The primary origin(s) of magnetism lies in

4

A long solenoid has 1000 turns per metre and carries a current of 1 A. It has a soft iron core of μr = 1000. The core is heated beyond the Curie temperature, Tc .

5

. Essential difference between electrostatic shielding by a conducting shell and magne-tostatic shielding is due to

6

Let the magnetic field on earth be modelled by that of a point magnetic dipole at the centre of earth. The angle of dip at a point on the geographical equator

7

A 25 cm long solenoid has radius 2 cm and 500 total number of turns. It carries a current of 15 A. If it is equivalent to a magnet of the same size and magnetisation M¯, then |M| is

8

Three needles N1 N2 and N3 are made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A magnet, when brought close to them, will
(?) attract N1 strongly, but repel N2 and N3 weakly.

9

The best material for the ore of a transformer is

10

Electromagnetic waves travelling in a medium having relative permeability μr = 1.3 and relative permittivity Er = 2.14. The speed of electromagnetic waves in medium must be

11

1.8 × 10² ms-1The condition under which a microwave over heats up a food item containing water molecules most efficiently is

12

The correct option, if speeds of gamma rays, X-rays and microwave are Vg, Vx and Vm respectively will be.

13

Waves in decreasing order of their wavelength are

14

The electric field associated with an e.m wave in vacuum is given by E?  =40 cos (kz – 6 × 108) i? , where E, Z and t are in volt/m, metre and seconds respectively. The value of wave vector K is

15

The oscillating magnetic field in a plane electromagnetic wave is given as By = (8 × 10-6) sin [2 × 1011t+ 300πx] T, wavelength of the em wave is

16

charged particle oscillates about its mean equilibrium position with a frequency of 109 Hz. The frequency of electromagnetic waves produced by the oscillator is

17

Light with an energy flux of 20 W/cm2 falls on a non-reflecting surface at normal incidence. If the surface has an area of 30 cm2, the total momentum delivered (for complete absorption) during 30 minutes is

18

Light with an energy flux of 20 W/cm2 falls on a non-reflecting surface at normal incidence. If the surface has an area of 30 cm2, the total momentum delivered (for complete absorption) during 30 minutes is

19

An electromagnetic wave travelling along z-axis is given as-E=E0 cos (kz – cot). Choose the incorrect option from the following;

20

A charged particle oscillates about its mean equilibrium position with a frequency of 109 Hz. For producing electromagnetic waves which one is not true?