UP PGT Physics Mock Test - 8 - UPTET MCQ

We know that centripetal acceleration, a = v x v /r
Here v = 6m/s and r = 0.3m
Thus a = 36 / 0.3 m/s²
= 120 m/s²

Brewster's angle is an angle of incidence at which light with a particular polarization is perfectly transmitted through a transparent dielectric surface, with no reflection. When unpolarized light is incident at this angle, the light that is reflected from the surface is therefore perfectly polarized.
So the angle of incidence would be 60°

We know moment of inertia of solid sphere I_s​=2​/5m_s​R_s²​ and 
moment of inertia of hollow sphere I_H​=2/3​m_H​R_H² ​As per question Is​=IH​
Now,
2/5​ms​Rs2​=2/3​mH​RH2​
as the masses are equal the ratio of their radii will be 
​R_s² /R_H² ​​=2/3​/​2/5​=√5/3​​=(5)^1/2: (3)^1/2

Dipole moment:

1. A dipole moment arises whenever a separation between the system
2. The formula of the dipole moment
   
3. The dimension formula for
   

Electric field intensity:

1. The electric field intensity is the strength of the electric field at the point
2. It is the force experienced by the unit positive charge in that point
   

where, F represents force, and the q₀ is the test charge.

        3. The dimension formula for Electric field intensity

Electric flux

1. The electric flux around an area inside an electric field is the total lines of forces passing through that area.
2. The equation of the electric flux:
   
3. The dimension formula for Electric flux
   

Hence, Option D is the correct answer.

Radio waves have wavelengths of 1mm to 100km. Hence, 21cm lies at short wavelength end of radio waves.

The molecules of air and other fine particles in the atmosphere have a size smaller than the wavelength of visible light. These particles are more effective in scattering light of a shorter wavelength at the blue end than the light of the longer wavelengths at the red end. The red light has a wavelength 1.8  times greater than blue light. Thus, when sunlight passes through the atmosphere, the fine particles in the air scatter the blue color more strongly than red color. The scattered blue light enters our eyes and we see the blue color of the clear sky.

The shape of the wave front in case of a light diverging from a point source is spherical and is shown in the given figure. The shape of the wavefront in case of a light emerging out of a convex lens when a point source is placed at its focus is a parallel grid.

On x-axis
A.  B=(μ0I/2πa)- (μ0I/2πa)=0
B.  On y axis say at (y, 0, 0)
B=[-μ0I/2π(a+y)]k + [μ0I/2π(a-y)]k
So except at origin, B has only z-components.
B cannot have x-component as B is perpendicular to direction of I. 
 

Since the charges are unlike, the force will be attractive. Thus the force directs from 1C to -4C.

In hooke's law, the constant of proportionality defines  the modulus of elasticity which is also defined as the ratio of internal reforming force / external deforming force.

Frequency=C/ λ
λ=h/P
frequency=C P/ h
f=(3×10⁸×3.3×10^-29)/6.6×10^-34
f=3× 10¹³/2
f=1.5×10¹³ Hz

Gravitational acceleration, g = GM / R² where M and R are mass and radius of star respectively.

So, Graph b describes g on the surface of the star as a function of radius.

We know that retardation of a car with an initial speed of 50kmph stops after 6 m.
We know that v² - u² = 2as  (third equation of motion)
► 0 - 50² = 2 * a * 6
► a = - 50² / 12
Hence when the initial speed is 100 kmph
We get,
► -100² = 2 * a * s
► 2 * s = 12 * (100² / 50²)
Thus we get s = 24 m.

Diffraction of light takes place for all types of waves transverse or longitudinal.

A non-polar substance consists of a huge number of dipoles in it, but they are oriented randomly and hence the net dipole moment of the substance becomes 0 and it acts as a non-polar substance. But if it is placed in an electric field, the dipoles present in it will orient themselves in the direction of the field and hence a net dipole moment will be observed, known as induced dipole moment. No current flow or oscillation of the substance will be observed.

Fringe width = λD/d
where λ us wavelength
D is the distance between slits & screen
d is the distance between slits

Yes, the angle of dip at a place is equal to 45^o, when the vertical and horizontal components of earth’s magnetic field are equal. In this case ➔ δ=45^o

So, B_V=B_H.

l = 1 m

= 314V

Here, thrust force is responsible to accelerate the rocket, so initial thrust of the blast

= ma

= 3.5 × 10⁴ × 10

= 3.5 × 10⁵ N

Sensitivity of the potentiometer means the smallest potential difference it can measure. It can be increased by reducing the potential gradient. The same is possible by increasing the length of the potentiometer. Hence the correct option is option C.

Total mechanical energy is 160
E_T = J
∴ U _max = 160 J

At extreme position KE is zero. Work done by spring force from extreme position to mean position is 

When an object is still held it is the part of a system in which the train is moving, once it is left it still has the same velocity as the train for a person from ground. Thus as the velocity is horizontal and acceleration is vertical, it would follow a parabolic trajectory.

Phase Difference between Current and EMF in an Inductance
 

• Explanation: In an inductance, the current lags behind the electromotive force (EMF) by a phase angle of π/2 (90 degrees).


• Reasoning: This phase difference occurs because when the current starts to flow through the inductance, it induces a back EMF that opposes the change in current. This back EMF leads to the current lagging behind the EMF.


• Mathematically: The relationship between the current (I) and the EMF (E) in an inductance can be expressed as: E = L(di/dt), where L is the inductance and di/dt is the rate of change of current with respect to time. This equation shows that the EMF is proportional to the rate of change of current, leading to the phase difference.


 

The line of action of F2 passes through the centre of rotation, and thus cannot produce a torque about the centre (r = 0).

This is because induced emf directly depends on relative motion between the magnet and coil, but if there is no relative motion between them, there will be no emf induced.

Shape of equipotential surfaces for a uniform electric field along x-axis are Planes normal to the field.

Spin and Orbital angular momentum arise due to the presence of unpaired electrons. If there are unpaired electrons, these momenta will be there otherwise not.

On smooth inclined plane:
Acceleration of the body = g sin θ If s be the distance travelled, then

We know that P=V²/R

For a given potential difference at a particular temperature

It is given that the powers of the bulbs are in the order 

100W > 60 W > 40W