If y = 5 cos (p x/3) sin 40 p t represents a stationary wave produced on a string, where x and y are in cm at t is in seconds, then the distance between consecutive nodes is:
1) p cm 2) 2 cm 3) 5 cm 4) 3 cm
In a Youngs double slit experiment the intensity at a point where the path-difference is $$\dfrac{\lambda}{6}$$ ( $$\lambda$$ being the wavelength of the light used) is $$I$$. If $$I_{0}$$ denotes the maximum intensity, $$\dfrac{I}{I_{0}}$$ is equal to
1) $$\dfrac{1}{\sqrt{2}}$$ 2) $$\dfrac{\sqrt{3}}{2}$$ 3) $$\dfrac{1}{2}$$ 4) $$\dfrac{3}{4}$$
An electric refrigerator rated 600W operates 8hours/day. What is the cost of the energy to operate it for 30 days at Rs.4.00 per kWh ? 1) Rs 576 2) Rs 144 3) Rs 57.60 4) Rs 14.40
The clinical thermometer acts as one kind of maximum thermometer because it (1) Contains mercury (2) Have thick glass walls (3) Is rather short in length (4) Has a constriction at the bottom of its capillary tube
A physical parameter a can be determined by measuring the parameters b, c, d and e using the relation a = bα cβ / dγ eδ. If the maximum errors in the measurement of b, c,d and e are b1%, c1%, d1% and e1 %, then the maximum error in the value of a determined by the experiment is 1) (b1 + c1 + d1 + e1)% 2) (b1 + c1 – d1 – e1)% 3) (αb1 + βc1 – γd1 – δe1)% 4) (αb1 + βc1 + γd1 + δe1)%
A car travels 90. meters due north in 15 seconds. Then the car turns around and travels 40. meters due south in 5.0 seconds. What is the magnitude of the average velocity of the car during this 20.-second interval? 1) 2.5 m/s 2) 5.0 m/s 3) 6.5 m/s 4) 7.0 m/s
What is the minimum energy required to launch a satellite of mass m from the surface of a planet of mass M and radius R in a circular orbit at an altitude of 2R ?
$$\begin{array}{1 1} (1)\;\large\frac{5GmM}{6R}\\ (2)\;\large\frac{2GmM}{3R} \\ (3)\;\large\frac{GmM}{2R}\\ (4)\;\large\frac{GmM}{3R}\end {array}$$
A circuit has a self-inductance of 1H and carries a current of 2A. To prevent sparking, when the circuit is switched off, a capacitor which can withstand 400V is used. The least capacitance of capacitor connected across the switch must be equal to
1) 50μF
2) 25μF
3) 100μF
4) 12.5μF
A transformer having efficiency of 90% is working on 200V and 3kW power supply. If the current in the secondary coil is 6A, the voltage across the secondary coil and current in the primary coil respectively are 1) 300V,15A 2) 450V,15A 3) 450V,13.5A 4) 600V,15A
A sonometre wire resonates with a given tuning forck forming standing waves with five antinodes between the two bridges when a mass of 9kg is suspended from the wire. When this mass is replaced by mass M, the wire resonates with the same positions of the bridges. Then find the value of square roof of M.
1) 5 2) 10 3) 25 4) none
In a double slit experiment, the two slits are 1 mm apart and the screen is place 1 m away. A monochromatic light of wavelength 500 nm is used. What will be the width of each slit for obtaining ten maxima of double slit within the central maxima of single slit pattern?
1) 0.5mm 2) 0.02mm 3) 0.2mm 4) 0.1mm
One mole of an ideal gas at 300 K in thermal contact with surroundings expands isothermally from 1.0 L to 2.0 L against a constant pressure of 3.0 atm. In this process, the change in entropy of surroundings (ΔSsurr) in JK-1 is (1 L atm = 101.3 J)
1) 5.763 2) 1.013 3) -1.013 4) -5.763
The velocity of light in a medium is 2 x 108 m /s. The refractive index of the medium is:
(1) 1.0 (2) 1.5 (3) 1.4 (4) 2.3
The pressure at the bottom of liquid tank is not proportional to
1.Acceleration due to gravity 2.Area of the liquid surface density of the liquid 3.Density of the liquid 4.Height of the liquid
Amplitude of a wave is represented by $$A=\frac{c}{a+b-c}$$ Then resonance will occur when
1) b = -c/2 2) b = 0 and a = c 3) b = - a/2 4) None of these
.If the escape velocity of a rocket from the surface of the Earth is ve , then the escape velocity of the same rocket from the surface of a planet whose acceleration due to gravity as well as radius are 3 times that of the Earth is 1) ve 2) ve / 3 3) 3 ve 4) 9 ve
The magnet of a vibration magnetometer is heated so as to reduce its magnetic moment by 36%. By doing this the periodic time of the magnetometer will: 1.Increase by 12.5% 2.Increase by 25% 3.Decrease by 12.5% 4.Decrease by 25%
A potentiometer wire of length 10m is connected in series with a battery. The e.m.f. of a cell balances against 250 cm length of wire. If length of potentiometer wire is increased by 1m, the new balancing length of wire will be 1) 2.00 m 2) 2.25m 3) 2.50m 4) 2.75m
A gaseous mixture contains 1 mole of a gas (γ=5/3)and another gas B (with γ=7/5) at a temperature T. Assuming that gases do not react with each other and behave ideally and γ for mixture is 19/13. The fraction of gas B in the mixture is 1) 2 / 3 2) 1 / 3 3) 1 4) 3 /4
The capacity of a parallel plate air capacitor is 2μF and voltage between the plates is changing at the rate of 3V/S. The displacement current in the capacitor is: 1) 2μF 2) 3μF 3) 5μF 4) 6μF
A copper wire of length ll is bent into a semicircle. It is moved with a velocity vv in a region where magnetic field is uniform and perpendicular to the plane of the wire. If the strength of the field is B then emf induced is 1) Blv 2) $$B\displaystyle \dfrac{l}{\pi}v$$ 3) $$B\displaystyle \dfrac{2l}{\pi}v$$ 4) none of these
A photon or quantum of light has wavelength ë and frequency f. Its energy is proportional to
1) 1/ë 2) f1/2 3) the light intensity 4) cë
Assuming an average energy of 200 MeV per fission, calculate the number of fissions per second needed for a 500 megawatt reactor. (1MeV is 1.60 x 10-13 Joules ) Assume (unrealistically) an efficiency of 100%.
1) 1.50 x 1024
2) 1.56 x 1019
3) 1.45 x 1022
4) 2.50 x 106
Which of the following statements are correct? (i) Centre of mass of a body always coincides withthe centre of gravity of the body. (ii) Centre of mass of a body is the point at whichthe total gravitational torque on the body is zero (iii) A couple on a body produce both translationaland rotational motion in a body. (iv) Mechanical advantage greater than one meansthat small effort can be used to lift a large load. 1) (ii) and (iv) 2) (i) and (ii) 3) (ii) and (iii) 4) (iii) and (iv)
A gas at temperature 2700C and pressure 30 atmospheres is allowed to expand to one atmospheric pressure. If the volume becomes 10 times its initial volumes, the final temperature becomes : 1) 100ooC 2) 373 K 3) 373oC 4) -173oC
The magnetic flux through a coil perpendicular to its plane and directed into paper is varying according to the relation ?=(2t2+4t+6) mWb. The emf induced in the loop at t = 4 s is: 1) 0.12 V 2) 2.4 V 3) 0.02 V 4) 1.2 V
The number of photo electrons emitted for light of a frequency v (higher than the threshold frequency v0) is proportional to :
1) Frequency of light (v) 2) $$v-v_0$$ 3) $$Threshold\;frequency\;(v_0)$$ 4) Intensity of light
The acceleration due to gravity g on earth is 9.8 ms -2 . What would the value of g for a planet whose size is the same as that of earth but the density in twice that of earth? 1) 19.6 ms-2 2) 9.8 ms-2 3) 4.9 ms-2 4) 2.5 ms-2
If the sum of all the forces acting on a moving object is zero, the object will
1) slow down and stop 2) change the direction of its motion 3) accelerate uniformly 4) continue moving with constant velocity
How many seconds does it take a metal ball to drop 200. m from rest? 1) 6.39 s 2) 4.28 s 3) 8.58 s 4) 7.29 s
In a triode amplifier phase between input and output voltages is :
(1) zero (2) p
(3) 2 p (4) p/2
The numerical aperture of objective of a microscope is 0.12. The limit of resolution, when light of wavelength 6000?A is used to view an object is:
1) 0.25×10−7m 2) 2.5×10−7m 3) 250×10−7m 4) 25×10−7m
If solar temp. is doubled then :
(1) it will emit infra red rays mainly
(2) it will emit ultra vilet rays mainly
(3) emission will be doubled
(4) emission will be four times
The pressure inside a tyre of a car is four times of atmospheric pressure and temp. 300 k. If the tyre is bursted all of sudden the new temperature will be (r = 7/5)
(1) 300 (4)-27 (2) 300 (4)2/7
(3) 300 (4)7/2 (4) 300 (2)7/2
In space charge limited region the plate voltage is 50 Volt and plate current is 100 mA. If the plate voltage is changed to 20 Volt, the plate current will become :
(1) 10 mA (2) 19 mA
(3) 25 mA (4) 40 mA
X-rays are :
(1) sound waves (2) em waves
(3) radio waves (4) all above
A car travels at 30 m/s. Seeing the cars in front of it begin to brake, it brakes and experiences an acceleration of –2 m/s2 for 4 seconds. What is its final speed?
1) 28 m/s
2) 14 m/s
3) 2 m/s
4) 22 m/s
If Rp= 7 k. and gm = 2.5 mili mho, how much the grid voltage must be changed when plate voltage is changed by 50 Volt, in order to keep plate current constant:
(1) + 2 Volt (2) – 4 Volt
(3) + 4 Volt (4) – 3 Volt
The circular divisions of shown screw gauge are 50. It moves 0.5 mm on main scale in one rotation. The diameter of the ball is 1) 2.25 mm 2) 2.20 mm 3) 1.20 mm 4) 1.25 mm
Two infinitely long straight conductors which are held parallel to each other at a distance 0.4m carry currents 20A and 10A in the same direction. The magnetic induction at a point midway between them is 1) 10−5 T 2) 3×10−5 T 3) 2×10−5 T 4) 10−6 T
A uniform ladder in static equilibrium leans against a frictionless wall. The ladder has length L and mass M. Given that the angle between the ladder and floor is 30o degrees, what would be the value of the coefficient of static friction (µs) between the ladder and the ground?
1) µs ≥ 1/ Ö3
2) µs ≥ 2/ Ö3
3) µs ≥ Ö3 / 2
4) µs ≥ 1/ 2
Radius of H-atom in its ground state is 5.03×10−11m. After collision with an electron it is found to have a radius of 20.12×10−11m.. The principal quantum number ′n′ of the final state of the atom is:
1) 1 2) 2 3) 3 4) 4
The equation of a stationary wave along a stretched string is given by $$y= 5 \sin\lgroup \dfrac{\pi x}{3} \rgroup \cos(40 \pi t)$$ Where x and y are in cm and t is in sec. The separation between two adjacent nodes is:
1) 3 2) 1.5 3) 6 4) 4
A beam of monochromatic ligh first travels through glass of R.I. 1.5 and then through water (R.I. =4/3). If the difference in their wavelength in the two media is 40nm, then the wavelength of the monochromatic light in vacuum will be 1) 4000 Å 2) 4400 Å 3) 4800 Å 4) 5200 Å
A non-conducting disc of radius a and uniform +ve surface charge density σ is placed on the ground with it 's axis vertical . A particle of mass m and +ve charge q is dropped , along the axis of the disc from a height H with zero initial velocity . Find the value of H if the particle just reaches the disk $$\;\large\frac{q}{m}=4 \in_{0} g/\sigma$$ . Find the position of particle at which the particle is in equilibrium
$$(1)\;\large\frac{2a}{\sqrt{3}}\qquad(2)\;\large\frac{a}{\sqrt{3}}\qquad(3)\;\large\frac{4a}{\sqrt{3}}\qquad(4)\;\large\frac{a}{3}1) 1 : 1$$
