Alternating Current — Physics STD 12 Science — Question

What type of wave front will emerge?
(i) From a point light source, (ii) From a remote light source.

The acceleration of a particle is zero as measured from an inertial frame of reference. Can we conclude that no force acts on the particle?

Steel is preferred for making permanent magnets whereas soft iron is preferred for making electromagnets. Give one reason.

A straight horizontal conducting rod of length 0.45 m and mass 60 g is suspended by two vertical wires at its ends. A current of 5.0 A is set up in the rod through the wires.

1. What magnetic field should be set up normal to the conductor in order that the tension in the wires is zero?
2. What will be the total tension in the wires if the direction of current is reversed keeping the magnetic field same as before? (Ignore the mass of the wires.) g = 9.8 m s^–2.

The thermal energy developed in a current-carrying resistor is given by U = i² Rt and also by U = Vit. Should we say that U is proportional to i² or i?

A diverging lens of focal length 20cm and a converging mirror of focal length 10cm are placed coaxially at a separation of 5cm. Where should an object be placed so that a real image is formed at the object itself?

A magnet of magnetic moment m is first cut perpendicular to its length and then perpendicular to its breadth into n equal parts, then calculate magnetic moment of each part.

What is the electrostatic potential due to an electric dipole at an equatorial point?

If the speed of a particle moving. at a relativistic speed is doubled, its linear momentum will:

1. Become double.
2. Become more than double.
3. Remain equal.
4. Become leas than double.