Hot questions

0 votes

0 answers

A long straight wire carrying current of 25A rests on a table as shown in Fig. Another wire PQ of length 1m, mass 2.5 g carries the same current but in the opposite direction. The wire PQ is free to slide up and down. To what height will PQ rise?

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

Electric Field LinesAn electric field line in general is a curve drawn in such a way that the tangent to it at each point is in the direction of the electric field at that point. A field line is a space curve, i.e. a curve in three dimensions. Electric field lines are thus used to pictorially map the electric field around a charge or a configuration of charges.The density of field lines is more near the charge. Away from the charge, the field is weak, so the density of field lines is less.Electric field lines always move

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

Two long conductors, separated by a distance d carry currents `I_1 and I_2` in the same direction. They exert a force F on each other. Now, the current in one of them is increased to two times and its direction is reversed. The distance is also increased to `3d`. The new value of the force between them

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

Self-Induction Self-induction is the property of a coil by virtue of which the coil opposes any change in the strength of current flowing through it by inducing an emf in itself. This induced emf is also called back emf. When the current in a coil is switched ON, then the self induction opposes the growth of the current and when it is switch OFF, then the self-induction opposes the decay of the current.The inductor has inductance `0.54 H` and carries a current that is decreasing at a uniform rate `(di)/(dt)=- 0.03` A/s, then dt the induced emf will

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

Find the position of the image formed by the lens combination given in the Fig.

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

In Millikan’s oil drop experiment an oil drop carrying a charge Q is held stationary by a p.d. 2400 v between the plates. To keep a drop of half the radius stationary the potential difference had to be made 600 v. What is the charge on the second drop

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

Photon is quantum of radiation with energy E = hν where ν is frequency and h is Planck’s constant. The dimensions of h are the same as that

asked Mar 19, 2022 in 11th Physics by varun (6.7k points)

0 votes

0 answers

Consider the charges q, q, and –q placed at the vertices of an equilateral triangle, as shown in Fig. . What is the force on each

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

What is the force between two small charged spheres having charges of 2 × 10–7C and 3 × 10–7C placed 30 cm apart in

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

A metallic spherical shell has an inner radius R1 and outer radius R2. A charge Q is placed at the centre of the spherical cavity. What will be surface charge density on the outer

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

Electrical energy is transmitted over large distances at high alternating voltages. Which of the following statements is (are)

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

A ring of radius r is rotating about its diameter with angular velocity `omega` in a perpendicular magnetic field `vecB` It has 20turns.The emf induced

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

A coil of inductance 300 mH and resistance `2Omega` is connected to a source of voltage 2V. The current reaches half of its steady state value

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

The core of a transformer is laminated so

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

In the circuit shown the capacitor has charge Q. At `t=0` sec the key is closed. The charge on the capacitor at the instant potential difference across the inductor `L_1` is zero,

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

Two identical looking iron bars A and B are given, one of which is definitely known to be magnetised. (We do not know which one.) How would one ascertain whether or not both are magnetised? If only one is magnetised, how does one ascertain which one? [Use nothing else

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

How many electrons pass through a lamp in 1 min, if the current is `300 mA`? Given, the charge on an electron is `1.6 xx 10^(-19)

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

The heat produced by 100W heater in 2 min is equal

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

Faraday’s Laws According to the Faraday’s first law, whenever the amount of magnetic flux linked with a circuit changes, an emf is induced in it. Induced current is determined by the rate at which the magnetic flux changes.Mathematically, the magnitude of the induced emf in a circuit is equal to the rate of change of magnetic flux through the circuit.Induced emf `prop` Rate of change of magnetic fluxWire loop is rotated in a magnetic field. The frequency of change of direction of the induced emf

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

0 votes

0 answers

A tank is filled with water to a height of 12.4 cm. The apparent depth of a needle lying at the bottom of the tank is measured by a microscope to be 9.3 cm. What is the refractive index of water? If water is replaced by a liquid of refractive index 1 .6 up to the same height, by what distance would the microscope have to be moved to focus on the needle

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

Hot questions

Categories