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On increasing the temperature of a conductor, its resistance increases because
Which of the following is discovered from the discharge tube experiment?
The fluctuation in the input voltage of 200 V to a domestic circuit is The power fluctuation will be
The average power dissipation in a pure capacitor in AC circuit is
A thin spherical conducting shell of radius R has charge q. Another charge Q is placed at the centre of the shell. The electrostatic potential at a point P at a distance R/2 from the centre of the shell is
The length of an elastic string is 'a' meters when the longitudinal tension is 4N and 'b' meters when the longitudinal tension is 5N. The length of the string in meters when the longitudinal tension is 9N is
The capacity of a condenser with two identical plates separated by a distance 'd' in air is 'C'. If the distance of separation is reduced to d 2 , the capacity is
A potential difference of 2V exists across a potentiometer wire of 2m length. When the potential difference across a 2Ω resistance of a second circuit is measured by this potentiometer wire, it amounts to 5mm balancing length. The current in the second circuit is
2.5 mA
Potential gradient in the wire
An electron revolves in a circle of radius 0.4 Å with a speed of 10^{6}ms^{−1} in a hydrogen atom. The magnetic field produced at the centre of the orbit due to the motion of the electron in tesla is [μ_{0} = 4π x 10^{−7}Hm^{−1} ; change on the electron = 1.6 x 10^{−19}C]
If a diamagnetic solution is poured into a Utube and one arm of this Utube is placed between the poles of a strong magnet, with the meniscus in line with the field, then the level of solution will
Sixty four spherical rain drops of equal size are falling vertically through air with a terminal velocity 1.5 ms^{⁻1}. If these drops coalesce to form a big spherical drop, then terminal velocity of big drop is
A body of mass 0.4 kg is whirled in a vertical circle making 2 rev/sec. If the radius of the circle is 2 m, then tension in the string when the body is at the top of the circle, is
A radioactive element has a half life of 15 years. The fraction that will decay in 30 years is
Two masses m₁ and m₂ are suspended together by a massless spring of spring cosntant k. When the masses are in equilibrium, m₁ is removed without disturbing the system, then the angular velocity of oscillation of m₂ is
A body A going from south to North and body B is going from west to east. Then direction of relative velocity of A with respect to B is
Which one of the following statements is true for the speed (ν) and the acceleration (α) of a particle simple harmonic motion?
A convex lens of focal length 0.5 m and concave lens of focal length 1 m are combined .The power of resulting lens will be
From a uniform wire, two circular loops are made i) P of radius 'r' and ii)Q of radius nr. If the moment of inertia of Q about an axis passing through its centre and perpendicular to its plane is 8 times that of P about a similar axis, the value of 'n' is (diameter of the wire is very much smaller than r or nr)
The depletion of layer in the pn junction region is caused by
If rotational kinetic energies of two bodies having moments of inertia of 9 kgm^{2} and 1 kgm^{2} are same, then ratio of their angular momenta is
since K.E. is same
Heat given to a body which rises its temperature by 1ºC is
The potential barrier, in the depletion of layer, is due to
A unit vector perpendicular to each of the vectors (6î+8k̂), (8î+6k̂) forming a right handed system is
A car moving with a speed of 40 km/h can be stopped by applying brakes after atleast 2m. If the same car is moving with a speed of 80 km/h, what is the minimum stopping distance ?
A 3 kg ball strikes a heavy rigid wall with a speed of 10 m/s at an angle of 60º .It gets reflected with the same speed and angle as shown .If the ball is in contact with the wall for 0.20 s, what is the average force exerted on the ball by the wall ?
A long, hollow conducting cylinder is kept coaxially inside another long, hollow conducting cylinder of larger radius.Both the cylinders are initially electrically neutral.
A copper cylindrical tube has inner radius a and outer radius b. The resistivity is ρ . The resistance of the cylinder between the two ends is
A car travels half the distance with constant velocity of 40 kmph and the remaining half with a constant velocity 60 kmph. The average velocity of the car in kmph is
Two identical straight wires are stretched so as to produce 6 beats per second when vibrating simultaneouly. On changing the tension slightly in one of them, the beat frequency remains unchanged. Denoting by T_{1}, T_{2} the higher and the lower initial tensions in the strings, then it could be said that while making the above changes in tension,
A charge q is placed at the centre of the joining two equal charges Q. The system of the three charges will be in equilibrium if q is equal to
A square loop ABCD of edge 'a' moves to the right with a velocity v, parallel to AB. There is a uniform magnetic field of magnitude B, directed into the paper, in the region between PQ and RS only. I, II and III are three positions of the loop. Then,
A charge q is uniformly distributed along the periphery of a nonconducting uniform circular disc pivoted at its centre in a vertical plane and can freely rotate about a horizontal axis passing through its centre. A cylindrical region with its axis passing through the centre of the disc has a varying magnetic field B = kt as shown in the adjacent figure.
Here, k is a positive constant and t is time. A block of mass m is suspended from one end of a massless and inextensible string wrapped over the disc as shown and remains stationary, then
A conducting sphere of radius R, carrying charge Q, lies inside an uncharged conducting shell of radius 2R. If they are joined by a metal wire,
The area under the forcedisplacement curve represents the work done.
It is the distance (s) of the object displaced by the application of the force (f). In this case force (f) is presented on the yaxis and displacement (s) on the xaxis.
The work done (w) is a scalar quantity.
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