## Physics Mock Test - I

### PHYSICS

##### Q 1.

In the circuit shown in the figure, reading of voltmeter is $$V_1$$ when only $$S_1$$ is closed, reading of voltmeter is $$V_2$$ when only $$S_2$$ is closed and reading of voltmeter is $$V_3$$ when both $$S_1$$and $$S_2$$ are closed, then

##### Q 2.

A certain body of mass M moves under the action of a conservative force with potential energy U given by $$U= \frac{Kx}{x^2+a^2}\ (x\to distance \to amplitude)$$

In this equation the units of K will be equal to that of:

##### Q 3.

The circuit shown here is used to compare the emf ‘s of the cells $$E_1\ and \ E_2 \ (E_1>E_2)$$ . When the galvanometer is connected to $$E_1$$ , the null point is at C. When the galvanometer is connected to $$E_2$$ , the null point will be

##### Q 4.
The coordinates of a moving particle at any time $$t$$ are given by $$x= ct^2\ and\ y =bt^2$$, the speed of the particle at time $$t$$ is given by:

##### Q 5.
At the mid-point along the length of a long solenoid, the magnetic field is equal to X. If the length of the solenoid is doubled and the current is reduced to half the field at the new mid-point will be nearest to

##### Q 6.
If the cable of a lift snaps while the lift is descending, then the weight as felt by the person inside the lift is

##### Q 7.
De Broglie wavelength of an alpha particle and a neutron are same then velocity of

##### Q 8.
The masses $$m_1$$ and $$m_2$$ are initially at rest and at infinite distance apart. They start moving towards one another under their mutual gravitational field. Their relative speed when they are at a distance d apart is:

##### Q 9.
The retarding potential for photoelectrons emitted when potassium having work function 0.3 eV is illuminated by light of wavelength 3300A° is

##### Q 10.
The height of mercury column in a simple barometer is $$h$$. As the tube is inclined with the vertical at an angle $$\alpha$$, the length of the mercury column along the length of the tube is $$l$$, then:

##### Q 11.
Consider the following reaction $$_1H^2+_1H^2\to \ _2He^4+Q$$. If $$m(_1H^2)=2.0141u;\ m(_2He^4)=4.0024u$$. The energy Q released (in MeV) in this fusion reaction is

##### Q 12.

The load versus elongation graph for the same material is shown in figure. The thinnest wire is represented by the line :

##### Q 13.
Difference in working of an amplifier and step up transformer is

##### Q 14.
If the work done in blowing a bubble of volume V is W then the work done in blowing a soap bubble of volume 2V will be:

##### Q 15.
The dominated waves associated with radiation emitted from a black body which is at a temperature 2.7 K belongs to (stefan’s constant b = $$2.88 \times 10^{-3}\ mK$$)

##### Q 16.
The ratio of radii of two spheres is 1:2 when they are dropped in a viscous liquid. The ratio of their terminal speeds is:

##### Q 17.
Which of the following is represents ‘action and reaction’ pair

##### Q 18.
A black body at a temperature T radiates at the rate of W watts. If the temperature of the body is reduced to T / 3, it will radiate at the rate of (in watts)

##### Q 19.
To increase both the resolving power and magnifying power of a telescope

##### Q 20.
A Carnot engine working between 300 K and 600 K has a work output of 800 J per cycle. The amount of heat energy supplied to the engine from the source in each cycle is

##### Q 21.
Two plane mirrors are placed perpendicular to each other. A ray strikes one mirror and after reflection falls on the second mirror. The ray after reflection from the second mirror will be

##### Q 22.

The height of a waterfall is 84 metre. Assuming that the entire kinetic energy of falling water is converted into heat, the rise in temperature of the water will be

$$(g=9.8m/s^2,J=4.2joules/Cal)$$

##### Q 23.
A clear sheet of polaroid is placed on the top of similar sheet so that their axes make an angle $$sin^{-1}\left (\frac 3 5 \right)$$ with each other. The ratio of intensity of the emergent light to that of unpolarised incident light is

##### Q 24.
Ten tuning forks are arranged in increasing order of frequency in such a way that any two nearest tuning forks produce 4 beats per sec. the highest frequency is twice that of the lowest. Possible highest and lowest frequencies (in Hz) are

##### Q 25.
In a n-p-n transistor circuit, the collector current is 10mA . If 90% of the electrons emitted reach the collector, the emitter current ( $$I_E$$) and base current ($$I_B$$)  are given by

##### Q 26.
A spherical mirror forms an image of the magnification 3. The object distance , if focal length of mirror is 24 cm, may be

##### Q 27.
A count rate meter shows a count of 240 per minute from a given radioactive source. One hour later the meter shows a count rate of 30 per minute. The half-life of the source is

##### Q 28.
The maximum value of index of refraction of a material of a prism which allows the passage of light through it when the refracting angle of the prism is A is:

##### Q 29.
In a nuclear reactor 0.01 mg of a fissile material is totally converted into energy in one second. The power of the reactor in MW is

##### Q 30.
An achromatic combination is made with a lens of focal length ' ' f and dispersive power ' '  with a lens having dispersive power of $$2\omega$$. The focal length of second will be

##### Q 31.
In an LCR circuit capacitance is changed from C to 2C. For the resonant frequency to remain unchanged, the inductance should be changed from L to

##### Q 32.
Two resistances $$R_1$$ and $$R_2$$ are made of different materials. The temperature coefficient of the material of $$R_1$$ is $$\alpha$$ and of the material of $$R_2$$ is −$$\beta$$. The resistance of the series combination of $$R_1$$ and $$R_2$$ will not change with temperature, if $$R_1$$/$$R_2$$ equals:

##### Q 33.
Dimensional formula of spring constant (k) is

##### Q 34.
A 100 W bulb working on 200 volts and a 200 W bulb working on 100 V have:

##### Q 35.

Two junction diodes one of Germanium (Ge) and other of silicon (Si) are connected as shown in figure to a battery of emf 12V and a load resistance 10k$$\Omega$$ . The germanium diode conducts at 0.3V and silicon diode at 0.7 . V When a current flows in the circuit, the potential of terminal Y will be

##### Q 36.
In the circuit shown here, what is the value of the unknown resistance R . For which the effective resistance of the circuit between points P and Q is also equal to R

##### Q 37.
A $$\frac 1 2$$ kg ball moves in a circle 0.4m of radius at a velocity of 4 m/s. Its centripetal acceleration is

##### Q 38.
In an electronic circuit, a cell, a variable resistance R and Ammeter are connected in series. A Voltmeter connected with the variable resistance to measure the voltage across the wire R and at one instant the reading of Ammeter and Voltmeter are 0.3 A and 0.9 V respectively. At other instant the values of Ammeter and Voltmeter are 0.25 A and 1.0 volt for other value of R. The internal resistance of the cell will be:

##### Q 39.
A solid ball of volume V is dropped in a viscous liquid. It experiences a viscous force F . If the solid ball of volume 8V is dropped in the same fluid, then the viscous force acting on it is

##### Q 40.
A proton and an alpha particle have equal kinetic energies. When they enter a field of magnetic induction B, moving at right angles to it, they describe circles. If $$r_p$$ and $$r_a$$ be the radii of the curvature respectively, then:

##### Q 41.
Transverse waves of same frequency are generated in two steel wires A and B . The diameter of A is twice that of B and the tension in A is half that of B. The ratio of velocities of waves in A and B is

##### Q 42.
In LCR circuit the capacitance is changed from C to 4 . C For the same resonant frequency, the inductance should be changed from L to

##### Q 43.
An ideal gas heat engine operates in a Carnot’s cycle between 227°C and 127°C . It absorbs $$6 \times 10^4J$$ of heat at high temperature. The amount of heat converted into work is

##### Q 44.

In the L-C-R series circuit the voltmeter and ammeter readings are:

##### Q 45.
The height from the earth’s surface at which the acceleration due to gravity is $$\frac 1 {100}\ th$$ of the value at the surface is [radius of the earth is R]