UP PGT Physics Mock Test - 4 - UPTET MCQ

(a) Speed of light in glass is c/μ=2×10⁸m/s

(b) The speed of light in glass is not independent of the colour of light. The refractive index of a violet component of white light is greater than the refractive index of a red component. Hence, the speed of violet light is less than the speed of red light in glass. Hence, violet light travels slower than red light in a glass prism.

Interference occurs for both transverse and longitudinal waves.
Interference does not indicate whether light is transverse or longitudinal since interference occurs for both types of waves.

Explanation:

Total power required to overcome a force of 165 N and to maintain a speed of 9.00 m/s

F = 165N

v = 9m/s

P = Fv = 165 x 9 = 1485 W

if each rider contribute equal power, then power required per rider will be P/2 = 1485/2 = 742.5W

I = mr², therefore it depends on body mass and its mass distribution.
 

An electric dipole is a separation of positive and negative charges. The simplest example of this is a pair of electric charges of equal magnitude but opposite sign, separated by some (usually small) distance. A permanent electric dipole is called an electret.

As, U=−Gm₁m₂/r, 
it can be used to describe the potential energy in a system of point charges (or radially symmetric spheres) as a function of their separation distance r, then the maximum value is zero at infinite separation.
Hence, its maximum value is zero at infinity.
 

Tension is uniformly transmitted if the springs are massless.

Temperature of black body should be more than zero. Obvious answer. If the temperature is not greater than 0 then there will be no radiation.

In free space, neither acceleration due to gravity for external torque act on the rotating solid sphere. Therefore, taking the same mass of sphere if the radius is increased then a moment of inertia, rotational kinetic energy and angular velocity will change but according to the law of conservation of momentum, angular momentum will not change.
In free space, neither acceleration due to gravity for external torque act on the rotating solid sphere. Therefore, taking the same mass of sphere if the radius is increased then a moment of inertia, rotational kinetic energy and angular velocity will change but according to the law of conservation of momentum, angular momentum will not change.

When liquid molecules are attracted strongly to themselves and weakly to those of solids, it costs lots of energy to create liquid-solid surface and liquid then does not wet the solid.

For Example: Mercury molecules (which make an obtuse angle with glass) have a strong force of attraction between themselves and a weak force of attraction toward solids. Hence, they tend to form drops.
On the other hand, water molecules make acute angles with glass. They have a weak force of attraction between themselves and a strong force of attraction toward solids. Hence, they tend to spread out.

When a light wave is reflected from an object , it changes not only it's amplitude but also its phase according to the properties of the object at a particular point. 
Therefore, option A is the right answer.

In equilibrium position, mg = k x₀

When the bullet gets embedded, the new equilibrium position changes.  Let it is a distance x from initial equilibrium position. 

Applying conservation of linear momentum, 

So, at t = 0, mass 3m/2   is at a distance mg/2k  from it mean position and moving up with velocity u/3

As the power of 10 is irrelevant to the determination of significant figures hence, the numbers of significant figures are 3 (1, 8 and 4).

Explanation:if a ball is thrown upward at an angle? The ball has a vertical and a horizontal component of velocity. The force of gravity is acting on it and its acceleration is in the downward direction. The vertical component of velocity is therefore changing. As the motion and acceleration is in opposite direction so vertical component of velocity decrease.

Clearly, the force is time-dependent.  

In air, all the colours of light travel with the same velocity with the same velocity, but in glass, velocities of different colours are different. Velocity of red colour is largest and velocity of violet colour is smallest. Therefore, after travelling through the glass slab, red colour will emerge first.

Let the acceleration of the cart be a, then normal reaction on cart is N = ma and frictional force between
block and cart is f = μN = μma.

For equilibrium, μma = mg ⇒ a = g/μ

Lenz’s law is used for determining the direction of induced current.
Lenz’s law of electromagnetic induction states that the direction of induced current in a given magnetic field is such that it opposes the induced change by changing the magnetic field.
Following is the formula of Lenz’s law:
ϵ=−N (∂ϕ_B/∂t)
Where,

• ε is the induced emf
• ∂ΦB is the change in magnetic flux
• N is the number of turns in the coil
   

Lenz’s law finds application in electromagnetic braking and in electric generators

The wire carries a current I in the negative z-direction.
We have to consider the magnetic vector field

Magnetic field is perpendicular to OP.

The  law states that the strain in a solid is proportional to the applied stress within the elastic limit of that solid body i.e. stress = k x strain.

Since the charge –q is moving in elliptical orbit so to make its motion stable the total angular momentum of the charge is constant since it experience a centripetal force from the charge +Q so it follow the motion as the motion of earth around sun.

There is no current inside the pipe. Therefore

This is the question based on impulse momentum theorem.

e = NBAω = 20 x 3 x 10^-2 x (3.14 x 0.08 x 0.08) x 50 = 0.603C

average power loss due to joule heating

PV=nRT

Hence the value of PV/T where the curves meet on the y-axis is 0.26 jK^-1

When the magnet is cut into three pieces the pole strength will remain the same and

We have, Magnetic moment (M) = Pole strength (m) × l

∴  New magnetic moment,

As the two identical coaxial circular loops carry a current i each circulating in the same direction, their flux add each other. When the two are brought closer, the total flux linkage increases. By Lenz's law a current will be induced in both the loops such that it opposes this change in flux. As the flux increases, the current in each loop will decrease so as to decrease the increasing flux.

Since friction is present in the scenario, so, only WET can be applied.