Physics Test - ...

A particle executes S.H.M. given by

$x=0·24\text{cos}\left(400t-0\text{.}5\right)$

in SI units. Find amplitude ?

In the circuit shown in diagram, the equivalent resistance between point A and B is

Two heavy metallic plates are joined together at 90° to each other. A laminar sheet of mass 30 kg is hinged at the line AB joining the two heavy metallic plates. The hinges are frictionless. The moment of inertia of the laminar sheet about an axis parallel to AB and passing through its centre of mass is 1.2 kg - m². Two rubber obstacles P and Q are fixed, one on each metallic plate at a distance 0.5 m from the line AB. This distance is chosen, so that the reaction due to the hinges on the laminar sheet is zero during the impact. Initially the laminar sheet hits one of the obstacles with an angular velocity 1 rad/s and turns back. If the impulse on the sheet due to each obstacle is 6N-s,

find the location of the centre of mass of the laminar sheet from AB.

The energy gap of pure \(\mathrm{Si}\) is \(1.1 \mathrm{eV}\). The mobilities of electrons and holes are respectively \(0.135 \mathrm{m}^{2} \mathrm{V}^{-1} \mathrm{s}^{-1}\) and \(0.048 \mathrm{m}^{2} \mathrm{V}^{-1} \mathrm{s}^{-1}\) and can be taken as independent of temperature. The intrinsic carrier concentration is given by

\(\mathbf{n}_{1}=\mathbf{n}_{0} \mathbf{e}^{-\mathbf{E}_{\mathbf{q}} / 2 \mathbf{k} \mathbf{T}}\)

where \(n_{0}\) is a constant, \(E_{g}\) the gap width and \(k\) the Boltzman's constant whose value is \(1.3810^{-23} \mathrm{JK}^{-1}\). Find the ratio of the electrical conductivities of Si at \(600 \mathrm{K}\) and \(300 \mathrm{K}\)

A vessel has the shape shown in figure. Water, which has density 10³kg/m³, is filled in the vessel. The pressure at the point A, ignoring the atmospheric pressure, is:

(Take g=10m/s²)

Equal volume of two immiscible liquids of densities ρ and 2ρ are filled in a vessel as shown in figure. Two small holes are made at depth h/2 and 3h/2 from the surface of lighter liquid. If v₁ and v₂ are the velocities of efflux at these two holes, then v₁/v₂ will be:

When an air bubble moves up from the bottom of a lake ?

a) velocity decreases and becomes zero

b) acceleration increases and becomes zero

c) velocity increases and becomes constant

d) acceleration decreases and becomes zero

If a body floats with (m/n)^th of its volume above the surface of water, then the relative density of the material of the body is:

Calculate the velocity of efflux of kerosene oil from an orifice of a tank in which pressure is 4atm. The density of kerosene oil = 720kgm⁻³and 1 atmospheric pressure = 1.013 × 10⁵Nm⁻².

Two sinusoidal plane waves of same frequencies having intensities I₀ and 4I₀ are travelling in the same direction . The resultant intensity at a point at which waves meet with a phase difference of zero radian is :