**JEE Physics paper set 1**

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2

A 60 HP electric motor lifts an elevator with a maximum total load capacity of 2000 kg. If the frictional force on

the elevator is 4000 N, the speed of the elevator at full load is close to (Given 1 HP = 746 W, g = 10 m=s2

3

A long solenoid of radius R carries a time (t) dependent current I(t) = I0t(1 ?? t). A ring of radius 2R is placed

coaxially near its middle. During the time instant 0 t 1, the induced current (IR) and the induced EMF (VR)

4

Two moles of an ideal gas withCp/Cv= 5=3 are mixed with 3 moles of another ideal gas with Cp /Cv= 4=3. The value of Cp /Cvfor the mixture is

5

The current (i1) (in A) flowing through 1 Ω

resistor in the following circuit is

6

8. Two infinite planes each with uniform surface charge density + C=m2 are kept in such a way that the angle

between them is 30o. The electric field in the region shown between them is given by:

7

If the magnetic field in a plane electromagnetic wave is given by ~B = 310??8 sin(1:6103x + 481010t)^j T

then what will be expression for electric field?

~E

= 310??8 sin(1:6103x+481010t)^i V=m a. ~E = 310??8 sin(1:6103x+481010t)^j b. V=m

~E

= 60 sin(1:6 103x + 48 1010t)^k V=m c. ~E d. = 9 sin(1:6 103x + 48 1010t)k^ V=m

8

The time period of revolution of electron in its ground state orbit in a hydrogen atom is 1:6 10??16s: The

frequency of revolution of the electron in its first excited state (in s??1) is :

9

A LCR circuit behaves like a damped harmonic oscillator. Comparing it with a physical spring-mass damped

oscillator having damping constant ’b’, the correct equivalence will be

10

The radius of gyration of a uniform rod of length l about an axis passing through a point l=4 away from the center

of the rod, and perpendicular to it, is

11

A satellite of mass m is launched vertically upward with an initial speed u from the surface of the earth. After it

reaches height R( R = radius of earth), it ejects a rocket of mass m=10 so that subsequently the satellite moves

in a circular orbit. The kinetic energy of the rocket is (G = gravitational constant; M is the mass of earth)

12

Three point particles of mass 1 kg, 1.5 kg and 2.5 kg are placed at three corners of a right triangle of sides 4.0

cm, 3.0 cm and 5.0 cm as shown in the figure. The centre of mass of the system is at the point

13

If we need a magnification of 375 from a compound microscope of tube length 150 mm and an objective of focal

length 5 mm, the focal length of the eye-piece should be close to:

14

Speed of transverse wave on a straight wire (mass 6:0 g, length 60 cm and area of cross-section 1:0 mm2) is 90

m=s. If the Young’s modulus of wire is 16 1011Nm??2, the extension of wire over its natural length is

15

1 liter of dry air at STP expands adiabatically to a volume of 3 litres. If

γ |

= 1:4, the work done by air is

(3^{1:4} = 4:655) (take air to be an ideal gas)