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An automobile moves on a road with a speed of $54 \text{ km h}^{-1}$. The radius of its wheels is $0.45 \text{ m}$ and the moment of inertia of the wheel about its axis of rotation is $3 \text{ kg m}^2$. If the vehicle is brought to rest in $15 \text{ s}$, the magnitude of average torque transmitted by its brakes to the wheel is:
An ideal gas is compressed to half its initial volume by means of several processes. Which of the following processes results in the maximum work being done on the gas?
1 g of water of volume $1 \text{ cm}^3$ at $100^{\circ}\text{C}$ is converted into steam at the same temperature under normal atmospheric pressure $\approx 1 \times 10^5 \text{ Pa}$. The volume of steam formed equals $1671 \text{ cm}^3$. If the specific latent heat of vaporization of water is $2256 \text{ J/g}$, the change in internal energy is:
During a cloudy day, a primary and a secondary rainbow may be created. Which of the following statement is correct?
A particle moves along a circle of radius $\frac{20}{\pi} \text{ m}$ with constant tangential acceleration. If the velocity of the particle is $80 \text{ m/s}$ at the end of the second revolution after motion has begun, the tangential acceleration is:
A light rod of length $l$ has two masses $m_1$ and $m_2$ attached to its two ends. The moment of inertia of the system about an axis perpendicular to the rod and passing through the centre of mass is:
A cup of coffee cools from $90^{\circ}\text{C}$ to $80^{\circ}\text{C}$ in $t$ minutes, when the room temperature is $20^{\circ}\text{C}$. The time taken by a similar cup of coffee to cool from $80^{\circ}\text{C}$ to $60^{\circ}\text{C}$ at room temperature same at $20^{\circ}\text{C}$ is:
RNA and DNA are chiral molecules, their chirality is due to:
In half-wave rectification, if the input frequency is $60\text{ Hz}$, the output frequency will be:
The output (X) of the logic circuit shown in the figure will be:
Which of the following is an example of forward biasing?
Consider the following statement : (A) Coenzyme or metal ion that is tightly bound to enzyme protein is called prosthetic group. (B) A complete catalytic active enzyme with its bound prosthetic group is called apoenzyme. Select the correct option.
A p-n photodiode is fabricated from a semiconductor with a band gap of $2.5\text{ eV}$. It can detect a signal of wavelength:
Given below are two statements: Statement I: Photovoltaic devices can convert optical radiation into electricity. Statement II: The Zener diode is designed to operate under reverse bias in the breakdown.
In the energy band diagram of a material shown below, the open circles and filled circles denote holes and electrons respectively. The material is a/an:
A thin rod of length $L$ and mass $M$ is bent at its midpoint into two halves so that the angle between them is $90^{\circ}$. The moment of inertia of the bent rod about an axis passing through the bending point and perpendicular to the plane defined by the two halves of the rod is:
The above figure shows the circuit symbol of a transistor. Select the correct statements given below: (A) The transistor has two segments of p-type semiconductor separated by a segment of n-type semiconductor. (B) The emitter is of moderate size and heavily doped. (C) The central segment is thin and lightly doped. (D) The emitter base junction is reverse biased in common emitter amplifier circuit.
A transistor is operated in a common emitter configuration at constant collector voltage $V_c = 1.5 \text{ V}$ such that a change in the base current from $100 \text{ } \mu\text{A}$ to $150 \text{ } \mu\text{A}$ produces a change in the collector current from $5 \text{ mA}$ to $10 \text{ mA}$. The current gain ($\beta$) is:
Which of the following statements are correct? (a) Centre of mass of a body always coincides with the centre of gravity of the body. (b) Centre of gravity of a body is the point about which the total gravitational torque on the body is zero. (c) A couple on a body produces both translational and rotational motion in a body. (d) Mechanical advantage greater than one means that small effort can be used to lift a large load.
Two particles are oscillating along two close parallel straight lines side by side, with the same frequency and amplitudes. They pass each other, moving in opposite directions when their displacement is half of the amplitude. The mean positions of the two particles lie on a straight line perpendicular to the paths of the two particles. The phase difference is: