Which of the following gives a reversible operation?
In a fluorescent lamp choke (a small transformer) 100 V of reverse voltage is produced when the choke current changes uniformly from 0.25 A to 0 in a duration of 0.025 ms. The self-inductance of the choke (in mH) is estimated to be __________ .
23
Sep
In a fluorescent lamp choke (a small transformer) 100 V of reverse voltage is produced when the choke current changes uniformly from 0.25 A to 0 in a duration of 0.025 ms. The self-inductance of the choke (in mH) is estimated to be __________ . Which of the following gives a reversible operation? September 23, [...]
A body of mass m = 10 kg is attached to one end of a wire of length 0.3 m. The maximum angular speed (in rad s^–1) with which it can be rotated about its other end in space station is (Breaking stress of wire = 4.8 × 10^7 Nm^–2 and area of cross-section of the wire = 10^–2 cm^2) is:
23
Sep
A body of mass m = 10 kg is attached to one end of a wire of length 0.3 m. The maximum angular speed (in rad s^–1) with which it can be rotated about its other end in space station is (Breaking stress of wire = 4.8 × 10^7 Nm^–2 and area of cross-section of [...]
One end of a straight uniform 1m long bar is pivoted on horizontal table. It is released from rest when it makes an angle 30º from the horizontal (see figure). Its angular speed when it hits the table is given as √ns-1, where n is an integer. The value of n is __________ .
23
Sep
One end of a straight uniform 1m long bar is pivoted on horizontal table. It is released from rest when it makes an angle 30º from the horizontal (see figure). Its angular speed when it hits the table is given as √ns-1, where n is an integer. The value of n is __________ . Which [...]
Both the diodes used in the circuit shown are assumed to be ideal and have negligible resistance when these are forward biased. Built in potential in each diode is 0.7 V. For the input voltages shown in the figure, the voltage (in Volts) at point A is __________ .
23
Sep
Both the diodes used in the circuit shown are assumed to be ideal and have negligible resistance when these are forward biased. Built in potential in each diode is 0.7 V. For the input voltages shown in the figure, the voltage (in Volts) at point A is __________ . Which of the following gives a [...]
A body A of mass m is moving in a circular orbit of radius R about a planet. Another body B of mass m/2 collides with A with a velocity which is half (vector v/2) the instantaneous velocity vector v of A. The collision is completely inelastic. Then, the combined body :
23
Sep
A body A of mass m is moving in a circular orbit of radius R about a planet. Another body B of mass m/2 collides with A with a velocity which is half (vector v/2) the instantaneous velocity vector v of A. The collision is completely inelastic. Then, the combined body : Which of the [...]
Three solid spheres each of mass m and diameter d are stuck together such that the lines connecting the centres form an equilateral triangle of side of length d. The ratio I0/IA of moment of inertia I0 of the system about an axis passing the centroid and about center of any of the spheres IA and perpendicular to the plane of the triangle is
23
Sep
Three solid spheres each of mass m and diameter d are stuck together such that the lines connecting the centres form an equilateral triangle of side of length d. The ratio I0/IA of moment of inertia I0 of the system about an axis passing the centroid and about center of any of the spheres IA [...]
Radiation, with wavelength 6561 Å falls on a metal surface to produce photoelectrons. The electrons are made to enter a uniform magnetic field of 3 × 10^–4 T. If the radius of the largest circular path followed by the electrons is 10 mm, the work function of the metal is close to
23
Sep
Radiation, with wavelength 6561 Å falls on a metal surface to produce photoelectrons. The electrons are made to enter a uniform magnetic field of 3 × 10^–4 T. If the radius of the largest circular path followed by the electrons is 10 mm, the work function of the metal is close to Radiation Which of [...]
A vessel of depth 2h is half filled with a liquid of refractive index 2√2 and the upper half with another liquid of refractive index √2. The liquids are immiscible. The apparent depth of the inner surface of the bottom of vessel will be :
23
Sep
A vessel of depth 2h is half filled with a liquid of refractive index 2√2 and the upper half with another liquid of refractive index √2. The liquids are immiscible. The apparent depth of the inner surface of the bottom of vessel will be : Which of the following gives a reversible operation? September 23, [...]
A charged particle of mass ‘m’ and charge ‘q’ moving under the influence of uniform electric field E vector i and a uniform magnetic field B vector k follows a trajectory from point P to Q as shown in figure. The velocities at P and Q are respectively, v i and -2v j. Then which of the following statements (A, B, C, D) are the correct ? (Trajectory shown is schematic and not to scale) :
23
Sep
A charged particle of mass ‘m’ and charge ‘q’ moving under the influence of uniform electric field E vector i and a uniform magnetic field B vector k follows a trajectory from point P to Q as shown in figure. The velocities at P and Q are respectively, v i and -2v j. Then which [...]
Three containers C1, C2 and C3 have water at different temperatures. The table below shows the final temperature T when different amounts of water (given in litres) are taken from each containers and mixed (assume no loss of heat during the process)The value of θ (in °C to the nearest integer) is ………
23
Sep
Three containers C1, C2 and C3 have water at different temperatures. The table below shows the final temperature T when different amounts of water (given in litres) are taken from each containers and mixed (assume no loss of heat during the process)The value of θ (in °C to the nearest integer) is ……… Three containers [...]