UP PGT Physics Mock Test - 6 - UPTET MCQ

x₁ + x₂ = l₁

Differentiating with respect to time,  we get v₁ + v₃ = 0

 Again differentiating w.r.t. time, 

III < II < IV < I.

We have, (1/v)−(1/−90)=1/f⇒(1.5−1)(1/30)=1/60
∴ v=180 cm
∴|m|=∣v/u∣=180/90=2.0

Microwaves are electromagnetic waves with wavelengths longer than those of terahertz (THz) wavelengths, but relatively short for radio waves. Microwaves have wavelengths approximately in the range of about one meter to one millimeter; with frequencies between 300 MHz (1 m) and 300 GHz (1 mm).

The magnetic field near the conducting rod due to long current carrying wire is 
B= μ₀​I/2πr ​ (using Ampere's law, ∫B.dl=μ_0​I)
Now, induced emf due to moving rod is e=Blv= (μ₀​I/2πr) ​×lv= μ₀​vIl/2πr

Calculate the area of the graph as area of v-t grph gives dis. 1/2×4×15=30

K = power × thickness (m) ÷ area × ∆T
K = (J s^-1) (m) ÷ (m²) (K)
K = J m^-1 s^-1 k^-1

Constructive interference occurs when the path differences (S₁​P−S₂​P) is an integral multiple of λ or (S₁​P−S₂​P)=nλ
Where n=0,1 ,2 3,….

If a particle is moving with angular velocity=ω
Its angle of rotation is given by ωt 
Now displacement= length of line AB
Position vector of a particle is given by
R =iacosωt + jasinωt
R_o=ai
displacement =R−R_o
=a(cosωt−1)i+asinωj
d=√[(a(cosωt-1))²+(asinω)²]
=a√(2(1-cosωt))=a√(2×2(sinωt/2)²)=2asinωt/2

The speed of any electromagnetic waves in free space is the speed of light c = 3x10⁸ m/s. Electromagnetic waves can have any wavelength λ or frequency f as long as λf = c.

In the transistor circuit, the current flows from emitter to collector via base.
I_e​=I_b​+I_c​ where variables have their usual meanings.
Hence, emitter current is slightly more than the collector current.

Centrifugal force, a fictitious force, peculiar to a particle moving on a circular path, that has the same magnitude and dimensions as the force that keeps the particle on its circular path (the centripetal force) but points in the opposite direction.

A small negatively charged body placed at X would be pushed to the right

The negative charge feels a force opposite to the direction of field.

 Other cases are not possible from properties of electric lines of force.

In calcite crystal there is a phenomenon of double refraction. So, we see one dot as a stationary object whereas the other being refracted at a little displaced position seems to be rotating about the first dot.

Work is the energy transferred to an object by force. It is a scalar quantity because it's the product of force and displacement. Work is not the same thing as force, which is a vector quantity, because work is the result of force.

= 4t-3
At t = 0.25s
e= 2V

Moment of inertia:

• Moment of inertia of a rigid body about a fixed axis is defined as the sum of the product of the masses of the particles constituting the body and the square of their respective distances from the axis of the rotation.
• The moment of inertia of a particle  is

⇒ I = mr²

Where r = the perpendicular distance of the particle from the rotational axis.

• Moment of inertia of a body made up of a number of particles (discrete distribution)

⇒ I = m₁r₁² + m₂r₂² + m₃r₃² + m₄r₄² + -------

EXPLANATION:

Given: mass of the particle = m, distance from x-axis = b.

The moment of inertia for the particle of mass m from an axis at a distance b is,

⇒ I = mb²

Therefore option 3 is correct.

Momentum of photo, p=E/c​=hν/c ​where E is the energy of a photon and c is the velocity of light. 
∴ p= hc/cλ ​    [∵ν=λc​]
p=h/λ​=h/(0.01×10−10)​=10¹²h

Time taken for 360° shift = 24 h
Time taken for 1° shift = 24/360 h = 4 min.
 

When 500 g is removed, m = (100 + 300)g = 0.4 kg 

When 300 g is also removed, 

• Diffraction occurs with all waves, including sound waves, water waves, and electromagnetic waves such as visible light, X-rays and radio waves. For the diffraction of wave, an obstacle or aperture of the size of the wavelength of the wave is needed.
• Since the wavelength of the radio waves is large and comparable with the size of the obstacles around which they bend. So it shows maximum diffraction.

Light as a wave: Light can be described (modeled) as an electromagnetic wave. In this model, a changing electric field creates a changing magnetic field. This changing magnetic field then creates a changing electric field and BOOM - you have light. Unlike many other waves (sound, water waves, waves in a football stadium), light does not need a medium to “wave” in.

The shape of equipotential surface for an infinite line charge is coaxial cylindrical because A curved surface on which potential is constant is equipotential curve . If we consider the line charge then the focus of the point should have the same potential hence it is a coaxial cylinder.

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

Explanation:As magnetic monopole does not exist. If we split the bar magnet into two pieces  each part will have its own north and south pole.

Since the object does not change its direction it means that the object is traveling in a straight line.
⇒ The path length and displacement will be equal.