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

Where,
D Represent : Dinesh
K Represent : Kunal
P Represent : Prashant
A Represent : Atul
N Represent : Nitin
Required distance = NA + AK + KD + DP = (25 + 40 + 60 + 90) m = 215 m

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

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.

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.

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

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.

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

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

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.

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.

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°.

Potential difference between two points is given by

V_a - V_b = W/q₀

Work, W = 2 J

Charge, q₀ = 20 C

Potential difference = 2/20 = 0.1 V

The correct option is C.

Definition based

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

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

e = Rate of change of magnetic field x area

=0.02×120×10⁻⁴=0.24mV

Given    P=50W, V_rms​=220V,
by     P=V_rms^2​​/R
or      R=V_rms²/P​​= 220²/50=968Ω
The peak voltage of the source is,
E_rms=E₀/√2
=>E₀=Erms x √2=220√2=311.13V
Now, 
I_rms​=V_rms​​/R
=220/968​
=0.227A
Hence option B is correct.

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.

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.

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.

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.

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.

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.

Given, the maximum kinetic energy: K_max​=4eV
If V0​ be the stopping potential, then K_max​=eV₀​
⇒eV_0​=4eV 
⇒V₀​=4V

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.

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.

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.