The diagrams below show regions of equipotential.
A positive charge is moved from \(\mathrm{A}\) to \(\mathrm{B}\) in each diagram. Choose the correct statement from the options given below:
1. | in all four cases, the work done is the same. |
2. | minimum work is required to move \(q\) in figure (a). |
3. | maximum work is required to move \(q\) in figure (b). |
4. | maximum work is required to move \(q\) in figure (c). |
Two astronauts are floating in gravitation-free space after having lost contact with their spaceship. The two will:
1. | move towards each other. |
2. | move away from each other. |
3. | become stationary. |
4. | keep floating at the same distance between them. |
The \(x\) and \(y\) coordinates of the particle at any time are \(x=5 t-2 t^2\) and \({y}=10{t}\) respectively, where \(x\) and \(y\) are in meters and \(\mathrm{t}\) in seconds. The acceleration of the particle at \(\mathrm{t}=2\) s is:
1. | \(5\hat{i}~\text{m/s}^2\) | 2. | \(-4\hat{i}~\text{m/s}^2\) |
3. | \(-8\hat{j}~\text{m/s}^2\) | 4. | \(0\) |
One end of the string of length \(l\) is connected to a particle of mass \(m\) and the other end is connected to a small peg on a smooth horizontal table. If the particle moves in a circle with speed \(v\), the net force on the particle (directed towards the center) will be: (\(T\) represents the tension in the string)
1. \(T+\frac{m v^2}{l}\)
2. \(T-\frac{m v^2}{l}\)
3. zero
4. \(T\)
A particle executes linear simple harmonic motion with amplitude of \(3~\text{cm}\). When the particle is at \(2~\text{cm}\) from the mean position, the magnitude of its velocity is equal to that of its acceleration. Then its time period in seconds is:
1. \(\frac{\sqrt5}{2\pi}\)
2. \(\frac{4\pi}{\sqrt5}\)
3. \(\frac{4\pi}{\sqrt3}\)
4. \(\frac{\sqrt5}{\pi}\)
Two polaroids \(P_1\) and \(P_2\) are placed with their axis perpendicular to each other. Unpolarised light of intensity \(I_0\) is incident on \(P_1\). A third polaroid \(P_3\) is kept in between \(P_1\) and \(P_2\) such that its axis makes an angle \(45^\circ\) with that of \(P_1\). The intensity of transmitted light through \(P_2\) is:
1. \(\frac{I_0}{4}\)
2. \(\frac{I_0}{8}\)
3. \(\frac{I_0}{16}\)
4. \(\frac{I_0}{2}\)
The bulk modulus of a spherical object is \(B.\) If it is subjected to uniform pressure \(P,\) the fractional decrease in radius is:
1. \(\frac{B}{3P}\)
2. \(\frac{3P}{B}\)
3. \(\frac{P}{3B}\)
4. \(\frac{P}{B}\)
In an electromagnetic wave in free space, the root mean square value of the electric field is \(E_{\text{rms}} = 6~\text{V/m}\). The peak value of the magnetic field is:
1. \(2.83\times 10^{-8}~\text{T}\)
2. \(0.70\times 10^{-8}~\text{T}\)
3. \(4.23\times 10^{-8}~\text{T}\)
4. \(1.41\times 10^{-8}~\text{T}\)
A rope is wrapped around a hollow cylinder with a mass of \(3\) kg and a radius of \(40\) cm. What is the angular acceleration of the cylinder if the rope is pulled with a force of \(30\) N?
1. \(0.25 ~\text{rad/s}^2 \)
2. \(25 ~\text{rad/s}^2 \)
3. \(5 ~\text{m/s}^2 \)
4. \(25 ~\text{m/s}^2 \)
Two discs of the same moment of inertia are rotating about their regular axis passing through centre and perpendicular to the plane of the disc with angular velocities \(\omega_1\) and \(\omega_2\). They are brought into contact face to face with their axis of rotation coinciding. The expression for loss of energy during this process is:
1. \(\frac{1}{4}I\left(\omega_1-\omega_2\right)^2\)
2. \(I\left(\omega_1-\omega_2\right)^2\)
3. \(\frac{1}{8}I\left(\omega_1-\omega_2\right)^2\)
4. \(\frac{1}{2}I\left(\omega_1-\omega_2\right)^2\)