Hot questions

0 votes

0 answers

Fig. shows the electric field lines around three point charges A, B and C. (a) Which charges are positive? (b) Which charge has the largest magnitude?

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

0 votes

0 answers

An e.m.f is produced in a coil, which is not connected to an external voltage source. This can be due

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

0 votes

0 answers

The diagram shows a capacitor C and resistor R connected in series to an ac source. V1 and V2 are voltmeters and Ais an ammeter, consider the following statements. (1) Readings in A and V2 are always in phase. (2) Reading in V1 is ahead in phase with reading in V2 . (3) Reading in A and V1 are always in phase. Which of these statements are / is

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

0 votes

0 answers

Radio receiver recives a message at 300m band, If the available inductance is 1 mH, then calculate required

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

0 votes

0 answers

Assertion: Upon displacement of charges within a closed surface, E at any point on the surface does change. Reason: The flux crossing through a closed surface is dependent on the location of charge within the

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

0 votes

0 answers

Assertion: Charge carriers do not move with acceleration but with a steady drift velocity. Reason: Charge carriers undergo collisions with ions and atoms during

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

0 votes

0 answers

EMF of a CellAn electric cell is a source of energy that maintains a continuous flow of charge in a circuit. It changes chemical energy into electrical energy. It has two electrodes, positive electrode and negative electrode as shown below.Electric cell has to do some work in maintaining the current through a circuit. The work done by the cell in moving unit positive charge through the whole circuit (including the cell) is called the electromotive force (emf) of the cell. For the given circuit, if the cell has an emf of `2 V` and the internal resistance of this cell

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

0 votes

0 answers

To ensure almost 100 per cent transmittivity, photographic lenses are often coated with a thin layer of dielectric material. The refractive index of this material is intermediated between that of air and glass (which makes the optical element of the lens). A typically used dielectric film is MgF2 (n = 1.38). What should the thickness of the film be so that at the center of the visible speetrum (5500 A o ) there is maximum transmission.

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

0 votes

0 answers

The force of repulsion between two point charges is F, when these are at a distance of 1 m. Now the point charges are replaced by spheres of radii 25 cm having the charge same as that of point charges. The distance between their centres is 1 m, then compare the force of repulsion in two

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

0 votes

0 answers

Coulomb’s law for electrostatic force between two point charges and Newton’s law for gravitational force between two stationary point masses, both have inverse-square dependence on the distance between the charges and masses respectively. Compare the strength of these forces by determining the ratio of their magnitudes (a) for an

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.The electric field lines of a negatively charged

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

0 votes

0 answers

In the circuit shown in figure below, the potential difference across the `4.5 muF` capacitor

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

0 votes

0 answers

Eddy CurrentCoil is wound over metallic core is helpful in reducing eddy currents in the metallic cores of transformers, electric motors, induction furnaces and other such devices (as shown below). Eddy currents are undesirable since they heat up the core and dissipate electrical energy in the form of heat. These currents are minimised by using laminations of metal to make a metal core. When a high frequency alternating current is passed through a coil which surrounds the metal to be melted,

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

0 votes

0 answers

(i) Explain the meaning of the statement ‘electric charge of a body is quantised’.(ii) Why can one ignore quantisation of electric charge when dealing with macroscopic i.e., large scale

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

0 votes

0 answers

Can the instantaneous power output of an ac source ever be negative? Can the average power output be

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

0 votes

0 answers

A transformer of efficiency 90% draws an input power of 4 kW. An electrical applience connected across the secondary draws a current of 6 A.The impedence of device

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

0 votes

0 answers

A metal rod of length 2 m rotates vertically about one of its end with frequency 2 Hz. The horizontal component of earth's magnetic field is `3.14xx 10^(-5)` then emf developed between two ends of road

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

0 votes

0 answers

The distance between the plates of a parallel plate capacitor is d. A metal plate of thickness (d/2) is placed between the plates. What will be the effect on the

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

0 votes

0 answers

Point charges 4µc and 2µc are placed at the vertices P and Q of a right angle triangle PQR respectively. Q is the right angle, `PR = 2 xx10^(-2) m` and `QR = 10^(-2) m` . The magnitude and direction of the resultant electric field at c is

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

0 votes

0 answers

In the LCR circuit shown in Fig , the ac driving voltage is `v = V_m sin ωt`. Describe subsequent motion of

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

Hot questions

Categories