Online Test

Question # 1

An aircraft is moving with a velocity of 300 ms^-1.If all the forces acting on it are balanced then

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It still moves with the same velocity

It will be just floating at the same point in space

It will be fall down instantaneously

It will lose its velocity gradually

The direction of magnetic lines of force is given by the

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Head to tail rule

Right hand rule

Left hand rule

None of these

A compound microscopes consists of objective of

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Very short focal length

Large focal length

Very large focal length

None of these

At the point of contact of the lens and the glass plate, the incident and reflected rays interfere

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constructively

destructively

either of them

none of them

The regions of the spring in which spring is stretched more than its normal position are called

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compressions

rarefactions

troughs

crests

A cube of metal is given a positive charge Q.For the above system,which of the following statements is true?

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Electric potential at the surface of the cube is zero

Electric potential within the cube is zero

Electric filed is normal to the surface of the cube

Electric field varies within the cube

An ideal op-amplifier has

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Infinite open loop gain

Infinite input resistance

Zero output resistance

All of these

The equations of pair production is

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hf = 2 m_oc² - KE(e^-) + K.E (e⁺)

hf = 2 m_oc² + KE(e^-) + K.E (e⁺)

hf = 2 m_o²c² + KE(e^-) + K.E (e⁺)

hf = 2 m_o²c + KE(e^-) + K.E(e⁺)

A tank containing water has an orifice in one vertical side. If the centre of the orifice is 10 m below the surface level in tank, then velocity of efflux is

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44 ms^-1

14 ms^-1

10 ms^-1

49 ms^-1

Reciprocal of bulk modulus is called

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Shear modulus

Compressibility

Young s modulus

None

X-rays are

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Positively charge

Negatively charged

Neutral

None of these

A and B are the two inputs of a NOR gate. Its output would be 1 when

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A=0,,B=1

A=1,B=0

A=1,B=1

A=0,B=0

For a simple harmonic oscillator the potential energy will be equal to the kinetic energy during a cycle

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At one point

At two point

At three points

At four points

Three particles having charges in the ratio of 1 : 2 : 3 produce the same point on the photographic film in the Thomson's experiment.Their masses are

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2 : 3 : 1

3 : 2 : 1

1 : 2 : 3

1 : 3 : 2

The typical speed of 100 meters dash

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2 ms^-1

4 ms^-1

10 ms^-1

12 ms^-1

The width of a depletion layer in a p-n junction is

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Increased by reverse biasing

Is independent of voltage

Increased by forward biasing

Decreased by reverse biasing

Acceleration increases ______ when rain drop starts to fall

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Very fast

Gradually

Very slow

No increase

In a p-type semiconductor germanium is doped with

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Gallium

Aluminium

Boron

All of above

The initial nucleus of uranium series is ₉₂U²³⁸ and the final nucleus is ₈₂Pb²⁰⁶.When uranium decays to lead how many α and β particles are produced?

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6, 8

8, 6

4, 3

3, 4

Under same environment the measurement of a physical quantity gives different values. The error in measurement is called

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Random error

Systematic error

Physical error

Uncertainty

The basic operations of Boolean algebra are

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AND,OR and NOT

AND and NOT

NAND,NOT and AND

NOR,NAND and OR

The typical example/examples of optically active crystals

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Quartz

Crystals of sodium chlorate

Crystals of sodium chloride

a and b

A heater coil is cut into tow equal part and only one part is now used in the heater. the Heat generated will now be

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Four times

Doubled

Halved

One fourth

What can be same for a photon an electron and a proton

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Charge

Mass

Velocity

De-brogile wave length

The Newton's formula for the velocity of sound is

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Relation between range and maximum range is

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R=R_max Sinθ

R=R_max Sinθ/2

R=R_max Sin2θ

R_max = RSin2θ

The principle of d.c. motor is based on

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Induced emf

Force due to magnetic field

Torque due to magnetic field

None of these

If a charge Q is dispersed over tow spheres of radii R and r such that their surface charge densities are equal. What is the ratio of the charges on the spheres?

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2r/R

R²_/r²

R³/5R³

R⁴/R⁴

In depletion region

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Holes are not present

Electrons are not present

Both are not present

None of these

Two charges are placed a certain distance apart in air when a dielectric sheet is placed between them, the electro static force between them will

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Decrease

Increase

Remain unchanged

Become zero

Solid state detector works under the

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forward biased condition

high temperature condition

reverse biased condition

high pressure condition

A system which deals with quantities or variables which have only two discrete values or states is called.

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Logic gates

Set

Digital system

A.C quantities

Ideal fluid is

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Steady flow

Non-viscous

Incompressible

All of these

Three resistors of resistance 2, 3 and 6 ohms are connected in parallel, their equivalent resistance is

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11.0 ohm

1.0 ohm

7.0 ohm

3.0 ohm

If the distance between two charges is doubled, the force between them will become:

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Double

Half

Three times

One fourth

One third

RBE of Neutrons and protons below 10 MeV is

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0.5 RBE

10.0 RBE

0.8 RBE

1.7 RBE

Low penetration power

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α-particle

β-particle

γ-particle

None of these

The vector product of two non zero vectors is zero when

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They are parallel to each other

They are perpendicular to each other

They are equal vectors

They are inclined at angle of 60°

Mirage is a phenomenon due to

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Reflection of light

Refraction of light

Total internal reflection of light

Diffraction of light

Electron microscope makes practical use of the

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Particle nature of electron

Wave nature of electron

Dual nature of electron

Neither particle nor wave nature of electron

When mass m = 0.50 kg and spring constant K = 245 kgs^-2. Find the time period of the system

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0.12 sec

0.20 sec

0.28 sec

0.29 sec