Physics Test - ...

The escape velocity of an atmospheric particle which is \(1000 \mathrm{km}\) above the earth's surface, is (radius of the earth is \(6400 \mathrm{km}\) and \(\left.\mathrm{g}=9.8 \mathrm{m} / \mathrm{s}^{2}\right)\)

The network shown in figure is a part of the circuit. (The battery has negligible resistance.)At a certain instant the current I = 5 A and is decreasing at a rate of 10 ³ As⁻¹.What is the potential difference between points B and A?choose the correct option from the given options.

Two sources of sound, \(S_{1}\) and \(S_{2}\), emitting waves of equal wavelength \(20.0 \mathrm{cm},\) are placed with a separation of \(20.0 \mathrm{cm}\) between them. \(\mathrm{A}\) detector can be moved on a line parallel to \(S_{1} S_{2}\) and at a distance of \(20.0 \mathrm{cm}\) from it. Initially, the detector is equidistant from the two sources. Assuming that the waves emitted by the sources are in phase, find the minimum distance through which the detector should be shifted to detect a minimum of sound.

A boat capable of a speed v in still water wants to cross a river of width d. The speed of the water current increases linearly from zero at either bank to a maximum of u at the middle of the river. When the boat is rowed at right angles to the bank, its downstream drift is

A single velocity time graph can be drawn for-

A square metal wire loop of side \(10 \mathrm{cm}\) and resistance \(1 \Omega\) is moved with constant velocity \(v_{0}\) in a uniform magnetic field of induction \(B=2 W b m^{-2},\) as shown in Figure. The magnetic field lines are perpendicular to the plane of loop and directed into the paper. The loop is connected to the network of resistances, each of value \(3 \Omega\). The resistance of the lead wire is negligible. The speed of the loop so as to have a steady current of \(1 \mathrm{m} A\) in the loop is

Four identical hollow cylindrical columns of mild steel support a big structure of mass 50,000 kg. The inner and outer radii of each column are 30 and 60cm respectively. Assuming the load distribution to be uniform, calculate the compressional strain of each column.

Directions: The following question has four choices, out of which ONE or MORE can be correct.

A particle of charge `q` and mass `m` moves rectilinearly under the action of an electric field E= α - βX . Here, and are positive constants, and `x` is the distance from the point where the particle was initially at rest.

Chose the correct option(s).

In nuclear reaction, energy released per fission is 200 MeV. When uranium 235 is used as nuclear fuel in a reactor having a power level of 1 MW, the amount of fuel needed in 30 days will be

The following question has four choices, out of which ONE or MORE can be correct.

Which of the following statements is/are correct?

Directions: The following question has four choices, out of which ONE or MORE can be correct.

In the given circuit, the

A reversible heat engine converts one-fourth of heat input into work. When the temperature of the sink is reduced by \(150^{\circ}\), its efficiency is doubled. The temperature of the source is:

The walls of a closed cubical box of edge \(50 \mathrm{cm}\) are made of a material of thickness \(1 \mathrm{mm}\) and coefficient of thermal conductivity \(4 \times\) \(10^{-4} \mathrm{cal} / \mathrm{s} / \mathrm{cm} /{ }^{\circ} \mathrm{C} .\) The interior of the box is maintained at \(100^{\circ} \mathrm{C}\) above the outside temperature by a heater placed inside the box and connected across \(400 \mathrm{V}\) d.c. The resistance of the heater is

A nonconducting insulating ring of mass \(\mathrm{m}\) and radius \(\mathrm{R}\), having charge Q uniformly distributed over its circumference is hanging by an insulated thread with the help of a small smooth ring (not rigidly fixed with bigger ring). A time varying magnetic field \(\mathrm{B}=\mathrm{B}_{0}\) sinwt is switched on at \(t=0\) and the ring is released at the same time. The induced EMF in loop at time \(t=2 \pi / \omega\) is:

A long cylindrical conductor of cross-sectional area A is made of a material whose resistivity depends only on the distance r from the axis of the conductor as \(p=\frac{\alpha}{r^{2}}\) where \(\alpha\) is a constant. The resistance per unit length of such a conductor is