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The ratio of frequencies of oscillations of two simple pendulums is 3: 4 then their lengths are in the ratio ______.
Concept: undefined >> undefined
In amplitude modulation. the amplitude of carrier wave is Ac and that of the modulating signal is Am· In practice, the ratio of Am to Ac is kept less than or equal to one, to avoid ______.
Concept: undefined >> undefined
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Six very long insulated copper wires are bound together to form a cable. The currents carried by the wires are l1 = + 10 A, l2 = -13 A, l3 = + 10 A, l4 = + 7 A, l5 = -12 A and l6 = + 18 A. The magnetic induction at a perpendicular distance of 10 cm from the cable is ______.
(µ0 = 4π x 10-7 Wb/A-m)
Concept: undefined >> undefined
The pointer reading v/s load graph for a spring balance is as given in the figure. The spring constant is ______.

Concept: undefined >> undefined
The range of the voltmeter is 'V' when 50 n resistance is connected in series. Its range gets doubled when 500 Ω resistance is connected in series. The resistance of voltmeter is ______.
Concept: undefined >> undefined
A particle starting from mean position oscillates simple harmonically with period 4 s. After what time will its kinetic energy be 75% of the total energy?
`( cos 30° = sqrt(3/2))`
Concept: undefined >> undefined
A cylindrical bar magnet (A) and similar unmagnetized cylindrical iron bar (B) are dropped through metallic pipe. The time taken to come down by ____________.
Concept: undefined >> undefined
A uniform metallic rod rotates about its perpendicular bisector with constant angular speed. If it is heated uniformly to raise its temperature to a certain value, its speed of rotation ______.
Concept: undefined >> undefined
A wheel of radius 2 cm is at rest on the horizontal surface. A point P on the circumference of the wheel is in contact with the horizontal surface. When the wheel rolls without slipping on the surface, the displacement of point P after half rotation of wheel is ______.
Concept: undefined >> undefined
The value of current 'I' in the given current distribution is ______
Concept: undefined >> undefined
An expression for oscillating electric field in a plane electromagnetic wave is given as Ez = 300 sin(5π × 103x - 3π × 1011t)Vm-1 Then, the value of magnetic field amplitude will be ______. (Given: speed of light in Vacuum c = 3 × 108 ms-1)
Concept: undefined >> undefined
Bx and By are the magnetic fields at the centre of two coils X and Y respectively each carrying equal current. If coil X has 200 turns and 20 cm radius and coil Y has 400 turns and 20 cm radius, the ratio of Bx and By is ______.
Concept: undefined >> undefined
At a certain place the angle of dip is 30° and the horizontal component of earth's magnetic field is 0.5 G The earth's total magnetic field (in G), a that certain place, is ______.
Concept: undefined >> undefined
The primary of a transformer has 400 turns while the secondary has 2000 turns. If the power output from the secondary at 1000 Vis 12 kW, what is the primary voltage?
Concept: undefined >> undefined
A current of I ampere flows in a wire forming a circular arc of radius r metres subtending an angle θ at the centre as shown. The magnetic field a the centre O in tesla is ______.

Concept: undefined >> undefined
A beam of electrons is moving with constant velocity in a region having simultaneous perpendicular electric and magnetic fields of strength 20 vm-1 and 0.5 T respectively at right angles to the direction of motion of the electrons. Then the velocity of electrons must be ______.
Concept: undefined >> undefined
The path length of oscillation of simple pendulum of length 1 meter is 16 cm. Its maximum velocity is ______. (g = π2 m/s2)
Concept: undefined >> undefined
A circular coil carrying current 'I' has radius 'R' and magnetic field at the centre is 'B'. At what distance from the centre along the axis of the magnetic field will be `"B"/8`?
Concept: undefined >> undefined
The ratio of magnetic fields due to a bar magnet at the two axial points P1 and P2 which are separated from each other by 10 cm is 25 : 2. Points P1 is situated at 10 cm from the centre of the magnet. Magnetic length of the bar magnet is ______.
(Points P1 and P2 are on the same side of magnet and distance of P2 from the centre is greater than distance of P1 from the centre of magnet)
Concept: undefined >> undefined
Two particles X and Y having equal charges after being accelerated through same potential difference enter a region of uniform magnetic field and describe a circular paths of radii r1 and r2 respectively. The ratio of the mass of X to that of Y is ______.
Concept: undefined >> undefined
