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Consider a simple circuit shown in the figure. R' stands for variable resistance. R' can vary from R₀ to infinity. r is the internal resistance of the battery (r<<R<<R₀). (a) Potential drop across AB is nearly constant as R' is varied. (b) Current through R' is nearly constant as R' is varied. (c) Current I depends sensitively on R'. (d) I ≥ V/(r+R) always. Which among the following statements is correct?
According to the kinetic theory of gases, at absolute zero temperature:
In the above diagram, the acceleration of the car will be:
A bob is whirled in a horizontal plane by means of a string with an initial speed of $\omega$ rpm. The tension in the string is $T$. If speed becomes $2\omega$ while keeping the same radius, the tension in the string becomes:
A motor cyclist moving with a velocity of $72 \text{ km/hour}$ on a flat road takes a turn on the road at a point where the radius of curvature of the road is $20 \text{ meters}$. The acceleration due to gravity is $10 \text{ m/sec}^2$. In order to avoid skidding, he must not bend with respect to the vertical plane by an angle greater than:
A solar cell is a:
A 1 kg stone at the end of 1 m long string is whirled in a vertical circle at a constant speed of 4 m/s. The tension in the string is 6 N, when the stone is at (Take g = 10 m/s²):
The electric field at a distance 3R/2 from the centre of a charged conducting spherical shell of radius R is E. The electric field at a distance R/2 from the centre of the sphere is
A uniform rope of length $l$ lies on a table. If the coefficient of friction is $\mu$, then the maximum length $l_1$ of the part of this rope which can overhang from the edge of the table without sliding down is:
Two masses of $5 \text{ kg}$ and $10 \text{ kg}$ are connected to a pulley as shown. What will be the acceleration of the system? ($g$ = acceleration due to gravity)
In a circuit shown in the figure, the heat produced in the 3 Ω resistance due to a current flowing in it is 12 J. The heat produced in the 4 Ω resistor is:
The dependence of the short wavelength limit $\lambda_{min}$ on the accelerating potential $V$ is represented by the curve of figure:
A silver wire has a resistance of 2.1 Ω at 27.5°C, and a resistance of 2.7 Ω at 100°C. The temperature coefficient of resistivity of silver is:
A long solenoid of diameter $0.1 \text{ m}$ has $2 \times 10^4$ turns per meter. At the centre of the solenoid, a coil of 100 turns and radius $0.01 \text{ m}$ is placed with its axis coinciding with the solenoid's axis. The current in the solenoid reduces at a constant rate to $0 \text{ A}$ from $4 \text{ A}$ in $0.05 \text{ s}$. If the resistance of the coil is $10\pi^2 \Omega$, the total charge flowing through the coil during this time is:
A block of mass $2 \text{ kg}$ is placed on an inclined rough surface $AC$ (as shown in the figure) of coefficient of friction $\mu$. If $g=10 \text{ m s}^{-2}$, the net force (in N) on the block will be:
The energy equivalent of 0.5 g of a substance is :
A certain metallic surface is illuminated with monochromatic light of wavelength $\lambda$. The stopping potential for photoelectric current for this light is $3V_0$. If the same surface is illuminated with light of wavelength $2\lambda$, the stopping potential is $V_0$. The photoelectric effect's threshold wavelength for this surface is?
A capacitor of $2 \mu\text{F}$ is charged as shown in the figure. When the switch S is turned to position 2, the percentage of its stored energy dissipated is:
The number density of free electrons in a copper conductor is $8.5 \times 10^{28} \text{ m}^{-3}$. How long does an electron take to drift from one end of a wire $3.0 \text{ m}$ long to its other end? (The area of cross-section of the wire is $2.0 \times 10^{-6} \text{ m}^2$ and it is carrying a current of $3.0 \text{ A}$).
In the Wheatstone's bridge shown, P = 2 Ω, Q = 3 Ω, R = 6 Ω and S = 8 Ω. In order to obtain balance, shunt resistance across 'S' must be [SCRA 1998]