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DSSSB PGT Physics Mock Test - 3 - DSSSB TGT/PGT/PRT MCQ


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30 Questions MCQ Test DSSSB PGT Mock Test Series 2024 - DSSSB PGT Physics Mock Test - 3

DSSSB PGT Physics Mock Test - 3 for DSSSB TGT/PGT/PRT 2025 is part of DSSSB PGT Mock Test Series 2024 preparation. The DSSSB PGT Physics Mock Test - 3 questions and answers have been prepared according to the DSSSB TGT/PGT/PRT exam syllabus.The DSSSB PGT Physics Mock Test - 3 MCQs are made for DSSSB TGT/PGT/PRT 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests for DSSSB PGT Physics Mock Test - 3 below.
Solutions of DSSSB PGT Physics Mock Test - 3 questions in English are available as part of our DSSSB PGT Mock Test Series 2024 for DSSSB TGT/PGT/PRT & DSSSB PGT Physics Mock Test - 3 solutions in Hindi for DSSSB PGT Mock Test Series 2024 course. Download more important topics, notes, lectures and mock test series for DSSSB TGT/PGT/PRT Exam by signing up for free. Attempt DSSSB PGT Physics Mock Test - 3 | 300 questions in 180 minutes | Mock test for DSSSB TGT/PGT/PRT preparation | Free important questions MCQ to study DSSSB PGT Mock Test Series 2024 for DSSSB TGT/PGT/PRT Exam | Download free PDF with solutions
DSSSB PGT Physics Mock Test - 3 - Question 1

Two vectors are equal if

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 1

Explanation:Equal vectors are vectors that have the same magnitude and the same direction. Equal vectors may start at different positions.

DSSSB PGT Physics Mock Test - 3 - Question 2

It is advised to drive along the slippery road slowly, because:

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 2

It is advised to drive along the slippery road slowly, because friction is reduced and if the driver is driving at a larger speed there is a risk of skidding.

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DSSSB PGT Physics Mock Test - 3 - Question 3

The angular acceleration is known as the rate of change of _________.

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 3

CONCEPT:

  • Angular displacement (θ): The angular displacement of a body is the angle in degrees or radians or revolutions through which a point revolves around a point or axis.
  • Angular velocity (ω): How fast the angular position or orientation of an object changes with time or How fast an object rotates or revolves relative to another point is known as angular velocity.
    • It is the rate of change of angular displacement.​
  • Angular acceleration (α): The rate of change of angular velocity is known as angular acceleration.
  • Angular momentum (L): The moment of momentum is known as angular momentum.

CALCULATION:

  • The rate of change of angular velocity is known as angular acceleration. 

Mathematically,

α = dω/dt

  • So the correct answer is option 3.
DSSSB PGT Physics Mock Test - 3 - Question 4

A ball of mass 10 g hits a hard surface vertically with a speed of 5 m/s and rebounds with the same speed. The ball remains in contact with the surface for 0.01 s. The average force exerted by the surface on the ball is  

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 4

Average force = change in momentum/time
Change in momentum = m(v1 - v2)
=0.01[ 5 - (-5)]
=0.1
Average force = 0.1/0.01
= 10 N

DSSSB PGT Physics Mock Test - 3 - Question 5

An earth satellite is moving around the earth in a circular orbit. In such case, what is conserved?

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 5

An earth satellite is moving in a circular motion due to change in the direction of velocity. Its angular momentum about centre is conserved as there is no external force acting on the system.

DSSSB PGT Physics Mock Test - 3 - Question 6

To complete one revolution around Earth, communication satellites take

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 6

A communications satellite is in a GEO (geostationary equatorial orbit) with a period of 24 hours. The spin rate ωs about its axis of symmetry is 1 revolution per minute, and the moment of inertia about the spin axis is 550 kg · m2.

DSSSB PGT Physics Mock Test - 3 - Question 7

When a solid is deformed,

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 7

Explanation:External force permanently distubed the equilibrium position of the interatomic ( or intermolecular ) forces between the particles of solid bodies.

DSSSB PGT Physics Mock Test - 3 - Question 8

The property by virtue of which the free surface of a liquid at rest behaves like an elastic stretched membrane tending to contract so as to occupy minimum surface area is known as

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 8

The property by virtue of which the free surface of a liquid at rest behaves like an elastic stretched membrane tending to contract so as to occupy minimum surface area is known as surface tension. By the definition of surface tension.

DSSSB PGT Physics Mock Test - 3 - Question 9

In an adiabatic process gas is reduced to quarter of its volume. What would happen to its pressure? Given ratio of specific heats γ= 2

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 9

Correct Answer : C

Explanation : The adiabatic condition is given by the relation between pressure volume and temperature volume as:

(PV)γ = constant 

where, γ = Cp/Cv is ratio of the specific heats

These relations suggest that an decrease in volume is associated with increase in temperature

 

ATQ 

P1(V1)γ = (P2V2

=> P1(1)2 = P2(4)2

P1/P2 = 16

DSSSB PGT Physics Mock Test - 3 - Question 10

Electric flux will be maximum if the angle between the field lines and area vector is ______

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 10

We know that the electric field and area both are vector quantity and the electric flux is expressed as E.s (taking dot product). But if the angle between the two vectors is θ then the formula becomes E-.s-.cosθ. Cosθ will be maximum if theta is zero, in all other cases, the value of Cosθ is less than 1. Therefore flux will be the maximum if the angle is 0 degrees.

 

DSSSB PGT Physics Mock Test - 3 - Question 11

What is the angle between the electric dipole moment and the electric field on the equatorial line of the dipole?

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 11

On equatorial line, the direction of electric field is reversed to that of angle of axial line. Therefore, the angle between dipole moment and electric field is 180°.

DSSSB PGT Physics Mock Test - 3 - Question 12

On moving a charge of 20 coulombs by 2 cm, 2 J of work is done, then the potential difference between the points is

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 12

Potential difference between two points is given by

Va - Vb = W/q0

Work, W = 2 J

Charge, q0 = 20 C

Potential difference = 2/20 = 0.1 V

The correct option is C.

DSSSB PGT Physics Mock Test - 3 - Question 13

Optical analogue of an equipotential surface is

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 13

Definition based

DSSSB PGT Physics Mock Test - 3 - Question 14

What will be the effect on capacitance, if the distance between the parallel plates reduced to one-third of its original value?​

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 14

C=(Kε0A/d)∝K/d
Hence,C1/C2=d2/d1=(d/3)d=3
C2=3C1

DSSSB PGT Physics Mock Test - 3 - Question 15

What should be the radius of an isolated spherical conductor so that it has a capacity of 2μF?​

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 15

Capacitance of an isolated spherical conductor =4π€R , where €=permittivity of vacuum
C=2×10-6F
C=4π€R
4×3.14×8.85×10-12×R=2×10-6
R=2×10-6/4×3.14×8.85×10-12
=1.8×104 m

DSSSB PGT Physics Mock Test - 3 - Question 16

The magnetic field between the Horizontal poles of an electromagnet in is uniform at any time, but its magnitude is increasing at the rate of 0.020 T/s.The area of a loop made of perfect insulating material is 120cm2.This loop is kept horizontally in the magnetic field. Induced emf and the induced current in the circuit are

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 16

e = Rate of change of magnetic field x area

 

=0.02×120×10−4=0.24mV

DSSSB PGT Physics Mock Test - 3 - Question 17

A light bulb is rated at 50W for a 220 V supply. The resistance of the bulb, the peak voltage of the source and the rms current through the bulb are

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 17

Given    P=50W, Vrms​=220V,
by     P=Vrms2​​/R
or      R=Vrms2/P​​= 2202/50=968Ω
The peak voltage of the source is,
Erms=E0/√2
=>E0=Erms x √2=220√2=311.13V
Now, 
Irms​=Vrms​​/R
=220/968​
=0.227A
Hence option B is correct.

DSSSB PGT Physics Mock Test - 3 - Question 18

A convex lens forms a real image of an object on a screen; the magnification of the image being 3/2. The object and the screen are kept fixed and the lens is moved through a distance of 16 cm when a sharp image is again formed on the screen; the magnification now being 2/3. What is the focal length of the lens?

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 18

3/2=v/u…...1
2/3=(v-16)/(u+16)......2
from these equation
we get v=48, u=32
so now f=(vxu)/(v+u)=96/5=19.2
The correct answer is option B.

DSSSB PGT Physics Mock Test - 3 - Question 19

For a rectangular slab, refraction takes place at

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 19

The refraction takes place at both the air-glass interface and glass-air interface of a rectangular glass slab. When the light ray incident on the air-glass interface (DC) obliquely, it bends towards the normal.

DSSSB PGT Physics Mock Test - 3 - Question 20

Critical angle is

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 20

The Critical Angle
a light ray is in the more dense medium and approaching the less dense medium.
The angle of incidence for the light ray is greater than the so-called critical angle.
When the angle of incidence in water reaches a certain critical value, the refracted ray lies along the boundary, having an angle of refraction of 90-degrees. This angle of incidence is known as the critical angle; it is the largest angle of incidence for which refraction can still occur. For any angle of incidence greater than the critical angle, light will undergo total internal reflection.

DSSSB PGT Physics Mock Test - 3 - Question 21

Waves on top of spectrum are

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 21

Infrared: Night vision goggles pick up the infrared light emitted by our skin and objects with heat. In space, infrared light helps us map the dust between stars.
Visible: Our eyes detect visible light. Fireflies, light bulbs, and stars all emit visible light.

Ultraviolet: Ultraviolet radiation is emitted by the Sun and are the reason skin tans and burns. "Hot" objects in space emit UV radiation as well.

X-ray: A dentist uses X-rays to image your teeth, and airport security uses them to see through your bag. Hot gases in the Universe also emit X-rays.

Gamma ray: Doctors use gamma-ray imaging to see inside your body. The biggest gamma-ray generator of all is the Universe.

DSSSB PGT Physics Mock Test - 3 - Question 22

A beam of light has a wavelength of 650 nm in vacuum. What is the wavelength of these waves in the liquid whose index of refraction at this wavelength is 1.47?

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 22

We know that,
Wavelength of light in a material:
λ= λ0/n
where, λ=wavelength of material, λ0=wavelength of light in vacuum,
n=index of refraction of material.
So, 650x10-9m/1.47=442.177nm.

DSSSB PGT Physics Mock Test - 3 - Question 23

A beam of light consisting of two wavelengths, 650 nm and 520 nm, is used to obtain interference fringes in a Young’s double-slit experiment. What is the least distance from the central maximum where the bright fringes due to both the wavelengths coincide?

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 23

DSSSB PGT Physics Mock Test - 3 - Question 24

Photoelectric effect is possible

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 24

Photoelectrons will come out from the surface of the metal only if it gets enough energy during the irradiation the energy needed depends on the metal and the max energy that can be provided on the light.

DSSSB PGT Physics Mock Test - 3 - Question 25

The maximum kinetic energy of photoelectrons emitted from a surface when photons of energy 6 eV fall on it is 4 eV. The stopping potential is

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 25

Given, the maximum kinetic energy: Kmax​=4eV
If V0​ be the stopping potential, then Kmax​=eV0
⇒eV0​=4eV 
⇒V0​=4V

DSSSB PGT Physics Mock Test - 3 - Question 26

Which of these statements about Bohr model applied to hydrogen atom correct?

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 26

A hydrogen atom has magnetic properties because the motion of the electron acts as a current loop. The energy levels of a hydrogen atom associated with orbital angular momentum are split by an external magnetic field because the orbital angular magnetic moment interacts with the field.

DSSSB PGT Physics Mock Test - 3 - Question 27

The name of a diode that can be used to provide a variable capacitance is:

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 27

The varactor diode is used in a place where the variable capacitance is required, and that capacitance is controlled with the help of the voltage. The Varactor diode is also known as the Varicap, Voltcap, Voltage variable capacitance or Tunning diode.

DSSSB PGT Physics Mock Test - 3 - Question 28

Photons of energy 1eV and 2.5 eV successively illuminate a metal whose work function is 0. 5 eV. The ratio of the maximum speeds of the electrons emitted will be

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 28
Work function=0.5
for 1ev photon
1ev=0.5+kinetic energy
k.E=0.5ev
for 2.5ev photon
2.5ev=0.5ev+k.E
k.E=2ev
ratio of above2 k.E give ratio of square of velocity =1:4
taking square root
finelly the ratio of velocity =1:2ans
DSSSB PGT Physics Mock Test - 3 - Question 29

The material which practically does not show elastic after effect is

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 29
When an elastic body is stretched and applied deforming force is removed then the body is expected to return to its original configuration instantaneously. This elastic after effect is very short for quartz fiber. But elastic after effect is more for glass.
DSSSB PGT Physics Mock Test - 3 - Question 30

State the part of the electromagnetic spectrum to which 1057 MHz (frequency of radiation arising from two close energy levels in hydrogen; known as Lamb shift)..Belongs

Detailed Solution for DSSSB PGT Physics Mock Test - 3 - Question 30

The frequency of radiation arising from the two close energy levels in hydrogen known as Lamb shift i.e. 1057 MHz is radio waves as it belongs to the short wavelength end of the electromagnetic spectrum. this wavelength correspond to microwave region of electromagnetic waves.

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