Two identical conducting balls having positive charges q₁ and q₂ are separated by a centre to centre distance r. If they are made to touch each other and then separated to the same distance, the force between them will be _____.

(a)

less than before

(b)

same as before

(c)

more than before

(d)

zero

A parallel plate capacitor stores a charge Q at a voltage V. Suppose the area of the parallel plate capacitor and the distance between the plates are each doubled then which is the quantity that will change?

(a)

Capacitance

(b)

Charge

(c)

Voltage

(d)

Energy density

What physical quantities may X and Y represent? [Y represents the first mentioned quantity].

(a)

K.E - velocity of a particle

(b)

pressure - temperature of a given gas (constant volume)

(c)

capacitance - charge to give a constant potential

(d)

potential - capacitance to give a constant charge

The electric flux is ________ if the electric field lines enter the closed surface.

(a)

positive

(b)

negative

(c)

zero

(d)

maximum

In India electricity is supplied for domestic use at 220 V. It is supplied at 110 V in USA. If the resistance of a 60 W bulb for use in India is R, the resistance of a 60 W bulb for use in USA will be ______.

(a)

R

(b)

2R

(c)

\(\frac{R}{4}\)

(d)

\(\frac{R}{2}\)

An unknown resistance is connected in parallel with a 15\(\Omega \) resistance and a 12V battery. What is the value of the unknown resistance if the current in the circuit is 2A?

(a)

\(10\Omega \)

(b)

\(20\Omega \)

(c)

\(30\Omega \)

(d)

\(40\Omega \)

Relation between current density and drift velocity is_________

(a)

en V_d

(b)

nAeV_d

(c)

\(\cfrac { n }{ e{ V }_{ d } } \)

(d)

\(\cfrac { { V }_{ d } }{ ne } \)

Three wires of equal lengths are bent in the form of loops. One of the loops is circle, another is a semi-circle and the third one is a square. They are placed in a uniform magnetic field and same electric current is passed through them. Which of the following loop configuration will experience greater torque?

(a)

Circle

(b)

Semi-circle

(c)

Square

(d)

All of them

The BH curve for a ferromagnetic material is shown in the figure. The material is placed inside a long solenoid which contains 1000 turns/cm. The current that should be passed in the solenoid to demagnetize the ferromagnet completely is _____.

(a)

1.00 m A

(b)

1.25 mA

(c)

1.50 mA

(d)

1.75 mA

The direction of the magnetic force on a positive charge moving in a magnetic field is given by ________________.

(a)

thumb rule

(b)

left hand rule

(c)

right hand rule

(d)

cork screw rule

These are behaving like thermistor ________________.

(a)

insulators and conductors

(b)

semiconductors and conductors

(c)

insulators and semiconductors

(d)

conductors and alloys

When the current changes from +2A to −2A in 0.05 s, an emf of 8 V is induced in a coil. The co-efficient of self-induction of the coil is

(a)

0.2H

(b)

0.4H

(c)

0.8H

(d)

0.1H

Consider an oscillator which has a charged particle oscillating about its mean position with a frequency of 300 MHz. The wavelength of electromagnetic waves produced by this oscillator is _____.

(a)

1 m

(b)

10 m

(c)

100 m

(d)

1000 m

The existence of E.M. waves was confirmed experimentally by __________________.

(a)

Hertz

(b)

Maxwell

(c)

Huygens

(d)

Planck

When a biconvex lens of glass having refractive index 1.47 is dipped in a liquid, it acts as plane sheet of glass. This implies that the liquid must have refractive index, ______.

(a)

less than one

(b)

less than that of glass

(c)

greater than that of glass

(d)

equal to that of glass

Two plane mirrors are at 45° to each other. If an object is placed between them then the number of images will be ________________.

(a)

5

(b)

9

(c)

7

(d)

8

A point object 0 is placed between two plane mirrors as shown in figure. The distance by mirror M₂ from it are _____________.

(a)

2 mm, 8 mm, 18 mm

(b)

2 mm, 18 mm, 28 mm

(c)

2 mm, 18 mm, 22 mm

(d)

2 mm, 18 mm, 58 mm

A convex mirror has a focal length f. A real object is placed at a distance Jin front the pole produces an image at ____________.

(a)

infinity

(b)

f

(c)

\(\cfrac { f }{ 2 } \)

(d)

2f

A concave mirror forms an image of sun at a distance of 12 cm from it __________.

(a)

The radius of curvature of this mirror is 6 cm

(b)

To use it as a shaving mirror, it must be held at a distance of 8 - 10 cm from the face

(c)

If an object is kept at a distance of 12 cm from it, the image formed will be same size as the object 

(d)

All the above

Sodium and copper have work functions of 2.3eV and 4.5eV respectively, then the ratio of the wavelengths is nearest to ___________.

(a)

1: 2

(b)

4: 1

(c)

2: 1

(d)

1: 4

Einstein's mass energy equivalence is _________

(a)

E = mc²

(b)

E = m₀c - mc²

(c)

E = (m₀ + m²)

(d)

E = m²c⁴

In a hydrogen atom, the electron revolving in the fourth orbit, has angular momentum equal to _____.

(a)

h

(b)

\(\frac{h}{\pi}\)

(c)

\(\frac{4h}{\pi}\)

(d)

\(\frac{2h}{\pi}\)

Energy of an atom at its ground state is ___________

(a)

zero

(b)

maximum

(c)

minimum

(d)

10 eV

To produce n-type semiconductor which impurity is added into the silicon?

(a)

B

(b)

Al

(c)

P

(d)

Mg

Radiowaves propagated through the troposphere of the earth are known as __________ waves.

(a)

space

(b)

surface

(c)

ground

(d)

sky