UP PGT Physics Mock Test - 9 - UPTET MCQ

By definition of Electric Field,

When equal charges are given to two spheres of different radii, the potential will be more or the smaller sphere as per the equation, Potential = Charge / Radius.
Since potential is inversely proportional to radius, the smaller radius will have higher potential and vice versa.

When friction is absent

a₁ = gsinθ

When friction is present

a₂ = gsin θ - μ_k gcos θ

From Eqs. (i) and (ii)

6g-T=6a
T=4a
6g-4a=6a
6g=10a
6x10=10a
6=a

The Particle Model of emission and absorption is based on the idea that light is composed of discrete particles called photons, and these photons carry quantized energy. This model helps us understand how atoms and molecules interact with light by either emitting or absorbing photons during electronic transitions.

There will be no current flowing in branch BE in steady condition.
Let I be the current flowing in the loop ABCDEFA.
Applying Kirchoff's law in the loop moving in anticlockwise direction starting from C. + 2V – I (2R) – I (R) – V = 0
∴V = 3IR
⇒ I = V/3R ... (1)

Applying Kirchoff's law in the circuit ABEFA we get on moving  in anticlockwise direction starting from B

+ V + Vcap – IR – V = 0 (where Vcap is the p.d. across capacitor).

Gravitational Potential is dened as the potential energy of a particle of unit mass at that point due to the gravitational force exerted byearth. Gravitational potential energy of a unit mass is known as gravitational potential.

Critical angle will be, sin⁻¹(1/1.5) = 41.8. The angle of incidence inside the prism will be 45. Since it is more than critical angle, the light ray will be internally reflected.

Φ= hνλ => 2eV= 6.626 x 10^-34 x ν

2 x 1.6 x 10^-19= 6.626 x 10^-34 x ν

On solving we get ν = 4.6 x 10¹⁴ Hz.

The Voltage Transformer can be thought of as an electrical component rather than an electronic component. A transformer basically is very simple static (or stationary) electro-magnetic passive electrical device that works on the principle of Faraday’s law of induction by converting electrical energy from one value to another.
 
The transformer does this by linking together two or more electrical circuits using a common oscillating magnetic circuit which is produced by the transformer itself. A transformer operates on the principles of “electromagnetic induction”, in the form of  Mutual Induction.
Mutual induction is the process by which a coil of wire magnetically induces a voltage into another coil located in close proximity to it. Then we can say that transformers work in the “magnetic domain”, and transformers get their name from the fact that they “transform” one voltage or current level into another.

Let the distance between any two charges is d. Therefore the net potential energy of the system is But the total energy of the system is zero. So, -qQ-qQ+ q²/2 

=0 that means q=4Q, i.e. q/Q=4.

Moment of Inertia = MR²
= 4 × 1
= 4 kg-m²

At the highest point in its trajectory, the acceleration (g) is acting in downward direction, whereas velocity of the projectile is only in the X (horizontal) direction.

To find the time it takes for the disc to come to a complete stop, we can use the formula:
ω = ω_₀ + αt

where:
ω = final angular velocity (0 rad/s, as the disc comes to a complete stop),
ω_₀ = initial angular velocity (200 rad/s),
α = angular acceleration, and
t = time.

Rearranging the formula to solve for time (t):
t = (ω - ω_₀) / α

Substituting the given values:
t = (0 - 200 rad/s) / (-10 rad/s²)
t = 20 seconds

Therefore, it will take 20 seconds for the disc to come to a complete stop.

 =1.5x0.22
 =15x22x10-3
 =330x10-3
Τ=0.33J
 

Conservation of angular momentum:
L= 2m dA/dt

From the diagram we can clearly see that ball A tends to float and ball B tends to sink, but they are unable because of the tension in the string. Thus we get d_A < d_F and  d_B > d_F
Thus we get that  d_A < d_F < d_B
Aslo making fbd of A and B gives 
 Vd_Ag + T =  Vd_Fg
and Vd_Fg + T =  Vd_Bg
Thus if we sun=btract above two equations we get
Vd_Ag +Vd_Bg  =  2Vd_Fg

There are three rules on determining how many significant figures are in a number:

• Non-zero digits are always significant.
• Any zeros between two significant digits are significant.
• A final zero or trailing zeros in the decimal portion ONLY are significant.

So, keeping these rules in mind, there are 1 significant digit.

In physics, two wave sources are perfectly coherent if they have a constant phase difference and the same frequency (amplitude may be different).
As c be the speed of light which is constant.
Using, c=νλ
Now same ν gives same λ. for the two light sources.
Example: y₁​=A₁​sinwt  and y_2​=A₂​sin(wt+ϕ) where ϕ is constant.

[P] = [F/A] = MLT^-2 / L²  = ML^-1T^-2
[F/V] = MLT^-2 / L3  = ML^-2T^-2
[E/V] = ML²T^-2 / L³  = ML^-1T^-2

The arrangement is shown in figure.

Now, draw the free body diagram of the spring balances and block. for equilibrium of block,

T₁ = Mg

where T₁ = Reading of S₂ For equilibrium of S₂.
T₂ = T₁

Where, T₂ 
 = Reading of S₁ For equilibrium of S₁, T₂ = T₃

Explanation:

Potential energy of spring converted in to potential energy

Given,
Number of turns, N = 500 turns
Radius of solenoid, r = 2.9
Relative permeability of annealed iron of Km=1400
Permeability of free space,  μ₀ =4π
The magnetic field, B=0.350 T
Therefore,
μ/μ₀= μ_r
μ= μ_r x μ₀
B= μ_rμ₀NI/2πR
0.350=1400x4x 3.14x500xI/2xπx2.90
I=72.mA
 

The Gauss law exists for all materials. Depending on the Gaussian surface of the material, we take the coordinate system accordingly. Suppose if the material is a coaxial cable, the Gaussian surface is in the form of a cylinder. Thus we take the cylinder/circular coordinate system.

for hot reservoir I.e. source
temperature T₁=400k
heat supplied Q₁=800J
For cold reservoir i.e. sink
Temperature T₂=?
Heat supplied Q₂=640J
According to carnot’s theorem,
Q₁/Q₂= T₂/T₁
640/800= T₂/400
T₂=320k

Statemen t-1 is tr ue. Sensitivity =. If  B increases, θ/I
increases. Statement-2 is wrong because soft  iron can be easily magnetised and de magnetized.

Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature.
Even near absolute zero, a real sample of a normal conductor shows some resistance. In a superconductor, the resistance drops abruptly to zero when the material is cooled below its critical temperature. An electric current flowing through a loop of superconducting wire can persist indefinitely with no power source.
Example: - Liquid Nitrogen.