Question # 1

Which combination of 7 identical resistors of 3-ohm will give 12/13 ohm:

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3 series, 4 parallel

5 series, 2 parallel

2 series, 5 parallel

4 series, 3 parallel

Where in standing wave, do the vibrations of the medium occur?

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Only at the nodes

Only at the antinodes

At all points between the nodes

At all points between the antinodes

A soap bubble is give a negative charge, then its radius:

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Decrease

Remains same

Increases

Bubble will disappear

Of electron of 50 keV strike a heavy target. Then radiation emitted by target will be

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Visible light

Radio waves

Ultraviolet

None of these

For a normal AC cycle, during T/2 to T the diode act as:

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Open switch

full wave rectifier

Close switch

All are correct

The gravity does no work, when the body moves:

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Horizontally

Vertically upwards

Vertically downward

At an angle of 45o with horizontal

The energy of photon of wavelength 1240 nm is:

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0.5 eV

1.0 eV

1.5 eV

2.0 eV

If velocity time graph is a straight line parallel to time axis then body is

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Moving with zero acceleration

Moving with constant velocity

Covering equal displacement in equal intervals of time

All of these

The diode charactristics curve is plot between

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I & t

V& t

V& I

None

Which statement about geostationary orbit is false?

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A geostationary orbit must be directly above the equator

All satellite in a geostationary orbit must have the same masses

The period of geostationary orbit must be 24 hours

There is only one possible radius for a geostationary

If a body changes its momentum from 100 N s to 200 N s in 10 s then the unbalanceexternal force responsible to change the momentum is

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5 N

2.5 N

2n

10n

If a source of emf is traversed from positive to negative the potential change will be:

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Positive

Negative

Zero

Constant

Two projectiles ‘A’ and ‘B’ are thrown with same speed but at angle of 40 degree and 50 degree with the horizontal. The horizontal range of ‘A’ will be:

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Equal to that of ‘B’

Greater than that of ‘B’

Less than that of ‘B’

4/5times that of ‘B’

In full wave rectification by bridge the number of diodes required are

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3

4

2

5

The simplest type of rectification known as half wave rectification is obtained by

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Using a transistor

Suppressing the harmonics in A.C. voltage

Suppressing half wave of A.C. supply by using diode

Using a Coolidge

The same retarding force is applied to stop a train. The train stops after 80 m. If the speed is doubled, then the Stopping distance will be:

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The same

Doubled

Halved

Four times

The unit of work function is

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eV

Volt

Farad

Herdz

In a full wave rectifier:

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DC current is twice that of half wave rectifier

DC pulses are twice per cycle that of half wave rectifier

DC voltage is twice that of half wave rectifier

All are correct

Which of the following have maximum ionization power?

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𝛼 −rays

𝛽 −rays

𝛾 −rays

Same for all

For atomic nucleus, the binding energy per nucleon with increase in mass number:

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Increases continuously

Remains same

Decrease continuously

First increases and then decreases with increase in mass number

A particle is moving with constant speed by keeping itself at constant distance from a fixed point in a given plane. Its motion is

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Circular motion

Uniform circular motion

Uniform circular motion with fixed axis of rotation

Uniform circular motion with axis of rotation not defined

If the magnitude of charge on each of two objects is doubled and the distance between them is also doubled then force between them:

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Doubled

Quadrupled

Halved

Remains same

The momentum of a particle is numerically equal to its K.E. What is the velocity of a particle?

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9 ms^-1

3 ms^-1

2 ms-1

1 ms^-1

A closed organ pipe and an open organ pipe have their first overtones of identicalfrequency. Their respective lengths are in the ratio:

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1 : 2

4 : 3

2 : 3

3 : 5

If a rotating body is moving counter clockwise, direction of angular velocity will be

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along linear velocity

towards the center

along the axis of rotation

away from center

A wave which consists of a single, non-repetitive disturbance is called a

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Continuous wave

Longitudinal wave

Pulse

Transverse wave

A stone is thrown upwards it returns to ground describing a parabolic path which of the following remains constant:

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Speed of the ball

Kinetic energy of the ball

Vertical component of velocity

) Horizontal component of velocity

The particles equal in mass or greater than mass of protons are called:

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Leptons

Mesons

Baryons

Quarks

First law of thermodynamics is merely a statement of law of conversation of:

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Energy

Angular momentum

Change

Linear momentum

Interference and diffraction confirm:

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Particle nature

Wave nature

Dual nature

None of these

A body moves a distance of 10 m along a straight line under the action of a force of 5 N. If the work done is 25 joules, the angle which the force makes with the direction of motion of the body is?

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0 Degree

30 Degree

60 Degree

90 Degree

Swimming is possible on account of

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1^st law of motion

2^nd law of motion

3^rd law of motion

Newton’s law of Gravitation

The example of nuclear fusion is:

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Formation of barium and krypton from uranium

Formation of plutonium -235 from uranium -235

Formation of helium from hydrogen

Formation of water from hydrogen and oxygen

The temperature at which all the gases become liquid is called:

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273 K

-273 K

Absolute Zero

Both (B) and (C)

The Balmer series is found in the spectrum of:

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Hydrogen

Nitrogen

Oxygen

All

The potential difference between head and tail of an "electric eel" can be upto.

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6V

60V

6000V

600V

Initially, four identical uniform blocks, each of mass m and thickness h, are spread on a table How much work is done on the blocks in stacking them on top of one another?

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2 mgh

3 mgh

4mgh

6mgh

When two semiconductors of p- and n-type are brought into contact, they from a p-n junction which act like a:

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Conductor

Amplifier

Oscillator

Rectifier

Ten second after an electric fan is turned on, the fan rotates at 300rev/min. its average angular acceleration is

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30 rad/s²

3.14 rad/s²

30 rev/s²

500 rev/s²

Photo cells is a device which convert light into:

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Wave nature

Particle nature

Particle wave nature

Dual nature

An elevator's motor produces 3000 W power. The speed With Which it can lift a 1000 kg load is:

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30.6ms^-1

0.306ms^-1

3.06ms^-1

300.3ms^-1