Consider a water tank as shown in the figure.
Consider a water tank as shown in the figure. It’s cross-sectional area is 0.4 m2. The tank has an opening... View Article
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Consider a 72 cm long wire AB as shown in the figure.
Consider a 72 cm long wire AB as shown in the figure. The galvanometer jockey is placed at P on... View Article
A ball of mass 4 kg, moving with a velocity of 10 ms-1, collides with a spring of length 8 m and force constant 100 Nm-1.
A ball of mass 4 kg, moving with a velocity of 10 ms-1, collides with a spring of length 8... View Article
Two wires of same length and thickness having specific resistances 6 Ω cm and 3 Ω cm respectively are connected in parallel. The effective resistivity is ρ Ω cm. The value of ρ, to the nearest integer, is ___
Answer: (4) In parallel, \(\begin{array}{l}R_{eq}=\frac{R_{1}R_{2}}{R_{1}+R_{2}}\end{array} \) \(\begin{array}{l}\frac{\rho l}{2A}=\frac{\rho _{1}\frac{l}{A}\times \rho _{2}\frac{l}{A} }{\rho _{1}\frac{l}{A}+\rho _{2}\frac{l}{A}}\end{array} \) \(\begin{array}{l}\Rightarrow \frac{\rho }{2}=\frac{6\times 3}{6+3}=2\end{array} \)... View Article
If the angular velocity of earth’s spin is increased such that the bodies at the equator start floating, the duration of the day would be approximately
If the angular velocity of earth’s spin is increased such that the bodies at the equator start floating, the duration... View Article
The speed of electrons in a scanning electron microscope is 1×107 ms-1.
The speed of electrons in a scanning electron microscope is 1×107 ms-1. If the protons having the same speed are... View Article
Which of the following statements are correct ?
Which of the following statements are correct ? (A) Electric monopoles do not exist whereas magnetic monopoles exist. (B) Magnetic... View Article
A particle of mass m moves in a circular orbit under the central potential field
A particle of mass m moves in a circular orbit under the central potential field, U(r)= -C/r, where C is... View Article
Consider a sample of oxygen behaving like an ideal gas. At 300 K, the ratio of root mean square (rms) velocity to the average velocity of gas molecule would be : (Molecular weight of oxygen is 32 g/mol; R=8.3 JK-1 mol-1)
a. \(\begin{array}{l}\sqrt{\frac{3}{3}}\end{array} \) b. \(\begin{array}{l}\sqrt{\frac{8}{3}}\end{array} \) c. \(\begin{array}{l}\sqrt{\frac{3\pi }{8}}\end{array} \) d. \(\begin{array}{l}\sqrt{\frac{8\pi }{3}}\end{array} \) Answer: (c) \(\begin{array}{l}V_{rms}=\sqrt{\frac{3RT}{M}}\end{array} \) And \(\begin{array}{l}V_{avg}=\sqrt{\frac{8RT}{\pi... View Article
Three rays of light, namely red (R), green (G) and blue (B) are incident on the face PQ of a right angled prism PQR as shown in the figure.
Three rays of light, namely red (R), green (G) and blue (B) are incident on the face PQ of a... View Article
The velocity – displacement graph of a particle is shown in the figure.
The velocity – displacement graph of a particle is shown in the figure. The acceleration – displacement graph of the... View Article
The angular momentum of a planet of mass M moving around the sun in an elliptical orbit is [latex]vec{L}[/latex]. The magnitude of the areal velocity of the planet is
a. L/M b. 2L/M c. L/2M d. 4L/M Answer: (c) Theoretical concept. ∴ Areal velocity, dA/dt=L/2M → L = Angular... View Article
Consider a uniform wire of mass M and length L. It is bent into a semicircle. Its moment of inertia about a line perpendicular to the plane of the wire passing through the centre is
a. \(\begin{array}{l}\frac{1}{2}\frac{ML^{2}}{\pi ^{2}}\end{array} \) b. \(\begin{array}{l}\frac{2}{5}\frac{ML^{2}}{\pi ^{2}}\end{array} \) c. \(\begin{array}{l}\frac{1}{4}\frac{ML^{2}}{\pi ^{2}}\end{array} \) d. \(\begin{array}{l}\frac{ML^{2}}{\pi ^{2}}\end{array} \) Answer: (d) ∵ L=πR... View Article
The function of time representing a simple harmonic motion with a period of π/ω is
a. cos(ωt) + cos(2ωt) + cos(3ωt) b. 3cos(π/4-2ωt) c. sin2(ωt) d. sin(ωt) + cos(ωt) Answer: (b) For expression, 3cos(π/4-2ωt) Angular... View Article
A proton and an α-particle, having kinetic energies Kp and Kα respectively, enter into a magnetic field at right angles.
A proton and an α-particle, having kinetic energies Kp and Kα respectively, enter into a magnetic field at right angles.... View Article
In a series LCR circuit, the inductive reactance (XL) is 10 Ω and the capacitive reactance (XC) is 4 Ω. The resistance (R) in the circuit is 6 Ω. Find the power factor of the circuit.
a. \(\begin{array}{l}\frac{1}{\sqrt{2}}\end{array} \) b. \(\begin{array}{l}\frac{\sqrt{3}}{2}\end{array} \) c. ½ d. \(\begin{array}{l}\frac{1}{2\sqrt{2}}\end{array} \) Answer: (a) Given : XL = 10 Ω XC... View Article
The correct relation between α (ratio of collector current to emitter current) and β (ratio of collector current to base current) of a transistor is
a. \(\begin{array}{l}\alpha =\frac{\beta }{1+\beta }\end{array} \) b. \(\begin{array}{l}\alpha =\frac{\beta }{1-\alpha }\end{array} \) c. \(\begin{array}{l}\beta =\frac{1 }{1-\alpha }\end{array} \) d. \(\begin{array}{l}\beta... View Article
For an adiabatic expansion of an ideal gas, the fractional change in its pressure is equal to (where λ is the ratio of specific heats)
a. \(\begin{array}{l}-\gamma \frac{dV}{V}\end{array} \) b. dV/V c. \(\begin{array}{l}-\frac{1}{\gamma } \frac{dV}{V}\end{array} \) d. \(\begin{array}{l}-\gamma \frac{V}{dV}\end{array} \) Answer: (a) For adiabatic expansion... View Article
The time taken for the magnetic energy to reach 25% of its maximum value, when a solenoid of resistance R, inductance L is connected to a battery, is
a. (L/R)ln2 b. (L/R)ln10 c. Infinite d. (L/R)ln5 Answer: (a) Magnetic energy, U=(½)LI2, when the current in the circuit is... View Article
An ideal gas in a cylinder is separated by a piston in such a way that the entropy of one part is S1 and that of the other part is S2. Given that S1 > S2. If the piston is removed then the total entropy of the system will be:
a. S1 + S2 b. S1 – S2 c. S1 × S2 d. S1/S2 Answer: (a) for gas 1 ,... View Article
