BITSAT Practice Test - 12 - JEE MCQ

Water has the highest specific heat capacity, so to raise the temperature of water by 1 °C very huge amount of heat is required and hence it is used as a coolant in car radiators and even as heater in hot water bags.

E = ML²T⁻² = MLT⁻² × (LT⁻¹) × T = FTV

Given, σ & −σ be the surface charge denisty, electric field between the plates,

Equilibrium position will be at the point where net force is 00.

Consider, X_o be the amplitude.

We know at equilibrium net force is 00.

So,

In beta minus decay (β ^–), a neutron is transformed into a proton and an electron is emitted with the nucleus along with an antineutrino.

where  the antineutrino.

A rectifier is an electrical device that converts alternating current to direct current.

Above diagram is the schematic diagram of diode used as half-wave rectifier.

When an A.C. source is given as input signal, for the first half of the signal diode will be in forward bias and the output signal is same as input. On the other hand, for the other half cycle, diode is in reverse bias, and it will behave as insulator in this case, so, no output will be recorded. 

Thus, rectifier converts A.C. input signal into D.C. output signal.

The ball is thrown at an angle θ with the horizontal. Thus,

u_x = 15cosθ

u_y = 15sinθ

In order to return at the same point, net displacement will be zero. Thus, in the horizontal direction,

and in the vertical direction,

⇒ t = 3sinθ ...(3)

from (1) we get, 

t = 10 cosθ  ...(4)
from Eq. (3) and (4), we get,

The direction of propagation of the electromagnetic wave is perpendicular to the variation of the electric field  and as well as to the magnetic field  as shown below.

By Applying the Right-hand rule for vector cross product, the direction of propagation of the wave is 

Here, Electric field oscillations is along Z-axis, Magnetic field oscillations is along X-axis and thus the propagation of electromagnetic wave will be along Y-axis.

Due to current in the wire, the flux through the ring will be zero. Hence the mutual inductance is zero.

As g' = g − ω²Rcos²λ

The latitude at a point on the surface of the earth is defined as the angle, which the line joining that point to the centre of the earth makes with equatorial plane.

It is denoted by, λ.

For the poles λ = 90° and for equator λ = 0°.
(i) Substituting λ = 90° in the above expression,

we get,

g_pole = g − ω²Rcos²90°

∴ g_pole = g

i.e., there is no effect of rotational motion of the earth on the value of g at the poles.
(ii) Substituting λ = 0° in the above expression,

we get,

g_equator = g − ω²Rcos²0°

∴ g_equator = g − ω²R
i.e., the effect of rotation of the earth on the value of g at the equator is maximum.

= 27 + 0 – (8 + 12) = 27 – 20 = +7 J
According to work energy theorem,
Change in the kinetic energy
= Work done, W
= +7 J

Both the diodes are in reverse biased.

The surface that we choose for the application of Gauss’s law is called Gaussian surface. A Gaussian surface is a closed surface in three-dimensional space through which the flux of a vector field is calculated, usually the gravitational field, the electric field, or magnetic field.

Given,

Number of turns in the coil, N = 400

The inductance of the coil, L = 8 mH

Current in the coil, i = 5 mA

Let the magnetic flux through each coil be ϕ, then

Viscosity is the property of fluids by the virtue of which it opposes any relative motion between the layers of fluid or between any object and fluid surrounding it. It is analogous to friction for fluids.
It depends strongly on temperature. In liquids, it usually decreases with increasing temperature, whereas, in gases, viscosity increases with increasing temperature.

If both Assertion and Reason are true and the Reason is correct explanation of the Assertion.

Let in time 't', the bus travel a distance 'x' and the person be behind the bus by a distance'd'.
In order to catch the bus, the person has to travel x + d in the same time.
x + d = ut

The equilibrium condition FBD of 2m

When the system is equilibrium, the spring force = 3 mg.
When the string is cut, the net force on block A = 3 mg - 2 mg = mg.
Hence, the acceleration of this block at this instant is

When the string is cut, the block B falls freely with an acceleration equal to g.

From eqs. (1) and (2), we get
which is choice (d).

Inside the shell, there is no mass. So, gravitational field is zero. Outside the shell, gravitational field is inversely proportional to the square of the distance.

As the block moves up with the fall of coin, l decreases, similarly h will also decrease because when the coin falls in water, it displaces water equal to its own volume only. The fall in level of water is higher from upward displacement of block. Hence, option b is correct.

Q₁ = T₀S₀ + 1/2 T₀S₀ = 3/2 T₀S₀
Q₂ = T₀(2S₀ - S₀) = T₀S₀ and Q₃ = 0

= 

Force between 2 charges in a medium = F' = 
∴ F' = 
In the given question, total effective distance = 
Therefore, force F = 
= 
= 1.73 × 10^-4 C

The force experienced by the current element is 
dl is the small current element of the loop and the force is acting perpendicular to the magnetic field as well as current element. So, the loop will expand.
Fleming's left hand rule: At any point, the force exerted by the magnetic field on the current element is directed outwards, and hence loop will expand.
Thus, the correct choice is (c).

I_g = Current for full-scale deflection = 4 x 10^-4 x 25 = 10^-2 ohm
R =  ohm in series

The impedance of the RLC circuit is Z = [(R² + (ωL - 1/ωC)²)]^1/2
= [(120)² + (42 - 2298.85)²]^1/2 = 2260 Ω
The phase angle is given by tan θ = (R/(ωL - 1/ωC)) or, tan θ = (120/(42 - 2298.85)) = (-120/2256.85) or, θ = -87^o

The person is myopic.
This defect is corrected by using a concave lens.
Putting u = -50 cm and v = -30 cm in the lens formula  gives f = -75 cm.
Therefore, the power of the lens = -1.33 D