Q. Oxygen is $16$ times heavier than hydrogen. Equal volume of hydrogen and oxygen are mixed. The ratio of speed of sound in the mixture to that in hydrogen is :

1. $\sqrt{23/17}$
2. $\sqrt{2/17}$
3. $\sqrt{8}$
4. $\sqrt{1/8}$

Q. A vertical circular coil of radius $0.1m$ and having $10$ turns carries a steady current. When the plane of the coil is normal to the magnetic meridian, a neutral point is observed at the centre of the coil. If $B_H=0.314\times {10}^{-4}T$, the current in the coil is :

1. $0.5A$
2. $0.25A$
3. $2A$
4. $1A$

Q. If two waves of same frequency and amplitude respectively on superposition produce a resultant disturbance of the same amplitude, the wave differ in phase by :

1. zero
2. $2\pi /3$
3. $\pi /3$
4. $\pi$

Q. A magnet $NS$ is suspended from a spring and when it oscillates, the magnet moves in and out of the coil $C$. The coil is connected to a galvanometer $G$. Then, as the magnet oscillates :

1. $G$ shows no deflection
2. $G$ shows deflection to the left and right but amplitude steadily decreases.
3. $G$ shows deflection to the left and right with constant amplitude.
4. $G$ shows deflection on one side.

Q. Two bodies of masses $1kg$ and $2kg$ have equal momentum. Then, the ratio of their kinetic energies is:

1. $3:1$
2. $1:1$
3. $1:3$
4. $2:1$

Q. A rectangular coil of $300$ turns has an average area of $25cm\times 10cm$. The coil rotates with a speed of $50cps$ in uniform magnetic field of strength $4\times {10}^{-2}T$ about an axis perpendicular to the field. The peak value of the induced emf is (in volt):

1. $3\pi$
2. $300\pi$
3. $3000\pi$
4. $30\pi$

Q. In an LCR circuit the potential difference between the terminal of the inductance is $60V$, between the terminals of the capacitor is $30V$ and that between the terminals of the resistance is $40V$. The supply voltage will be equal to:

1. $130V$
2. $10V$
3. $50V$
4. $70V$

Q. An electron is accelerated through a potential difference of 45.5 volt. The velocity acquired by it is (in $m{s}^{-1}$) :

1. ${10}^6$
2. zero
3. $4\times {10}^6$
4. $4\times {10}^4$

Q. The spectrum obtained from the chromosphere of the sun at the time of total solar eclipse is :

1. continuous emission spectrum
2. line emission spectrum
3. band emission spectrum
4. line absorption spectrum

Q. What is the dimensional formula of Inductance?

1. $\left[M{L}^{2}T{A}^{-2}\right]$
2. $\left[M{L}^2{T}^{-2}{A}^{-2}\right]$
3. $\left[M{L}^2{T}^{-1}{A}^{-2}\right]$
4. $\left[M{L}^2{T}^{-2}{A}^{-1}\right]$

Q. A bullet moving with a speed of $100m{s}^{-1}$ can just penetrate two planks of equal thickness. Then, the number of such planks penetrated by the same bullet when the speed is doubled will be :

1. 6
2. 10
3. 4
4. 8

Q. The maximum current that can be measured by a galvanometer of resistance $40\Omega$ is $10mA$. If it is converted into a voltmeter that can read upto $50V$. the resistance to be connected in series with the galvanometer (in ohms) is:

1. $5040$
2. $4050$
3. $2010$
4. $4960$

Q. When a body moves in a circular path, no work is done by the force since :

1. the force is always away from the centre.
2. force and displacement are perpendicular to each other.
3. there is no displacement.
4. there is no net force.

Q. A beam of light of wavelength $600nm$ from a source falls on a single slit $1mm$ wide and the resulting diffraction pattern is observed on a screen $2m$ away. The distance between the first dark fringes on either side of the central bright fringe is:

1. $2.4mm$
2. $2.4cm$
3. $1.2mm$
4. $1.2cm$

Q. Absorption coefficient of an open window is :

1. zero
2. $1$
3. $0.5$
4. $0.25$

Q. Heavy water is:

1. compound of deutrium and oxygen
2. water at $4^{\circ }C$
3. compound of heavy oxygen and heavy hydrogen
4. water, in which soap does not lather

Q. The loudness and pitch of a sound note depend on :

1. intensity and velocity
2. frequency and velocity
3. intensity and frequency
4. frequency and number of harmonics

Q. Curie-Weiss law is obeyed by iron :

1. at Curie temperature only.
2. at all temperatures.
3. below Curie temperature.
4. above Curie temperature.

Q. A spherical drop of capacitance $1\mu F$ is broken into $8$ drops of equal radius. Then, the capacitance of each small drop is:

1. $\frac{1}{2}\mu F$
2. $8\mu F$
3. $\frac{1}{4}\mu F$
4. $\frac{1}{8}\mu F$

Q. SI unit of permitivity is:

1. $C^2{m}^2{N}^2$
2. $C^2{m}^{-2}{N}^{-1}$
3. $C^{-1}{m}^2{N}^{-2}$
4. $C^2{m}^2{N}^{-1}$

Q. The difference between the apparent frequency of a source of sound as perceived by the observer during its approach and recession is $2\%$ of the frequency of the source. If the speed of the sound in air is $300ms$, the velocity of the source is :

1. $1.5ms$
2. $12ms$
3. $6ms$
4. $3ms$

Q. Three long straight wires A, B and C are carrying currents as shown in figure. Then the resultant force on B is directed :

1. towards A
2. perpendicular to the plane of the paper and outward
3. perpendicular to the plane of the paper and inward
4. towards C

Q. An unknown resistance $R_1$ is connected in series with a resistance of $10\Omega$. This combination is connected to one gap of a meter bridge while a resistance $R_2$ is connected in the other gap. The balance point is at $50cm$. Now when the $10\Omega$ resistance is removed, the balance point shifts to $40cm$. The value of $R_1$ is (in ohms) :

1. $10$
2. $20$
3. $60$
4. $40$

Q. In the circuit shown, the internal resistance of the cell is negligible. The steady state current in the $2\Omega$ resistor is :

1. $0.6A$
2. $1.2A$
3. $0.9A$
4. $1.5A$

Q. A thread is tied slightly loose to a wire frame as in figure and the frame is diped into a soap solution and taken out. The frame is completely covered with the film. When the portion A is punctured with a pin, the thread :

1. becomes concave towards A
2. becomes convex towards A
3. either (a) or (b) depending on the size of A with respect to B
4. remains in the initial position

Q. The nuclear reactor at Kaiga is a :

1. research reactor
2. fusion reactor
3. breedor reactor
4. power reactor

Q. Two equal forces ($P$ each) act at a point inclined to each other at an angle of ${120}^0$. The magnitude of their resultant is:

1. $P/2$
2. $P/4$
3. $2P$
4. $P$

Q. A man, standing between two cliffs, claps his hands and starts hearing a series of echoes at intervals of one second. If the speed of sound in air is $340m{s}^{-1}$, the distance between the cliffs is :

1. $680m$
2. $1700m$
3. $340m$
4. $1620m$

Q. In Melde's experiment in the transverse mode, the frequency of the tuning fork and the frequency of the waves in the string are in the ratio :

1. 1:1
2. 1:2
3. 4:1
4. 2:1

Q. H-polaroid is prepared by:

1. orienting herapathite crystal in the same direction in nitrocellulose.
2. using them tourmaline crystals.
3. stretching polyvinyl alcohol and then heated with dehydrating agent
4. stretching polyvinyl alcohol and then impregnating with iodine