The earth's magnetic field varies from point to point in space. Does it also change with time? If so, on what time scale does it change appreciably?

A magnetic field that varies in magnitude from point to point but has a constant direction (east to west) is set up in a chamber. A charged particle enters the chamber and travels undeflected along a straight path with constant speed. What can you say about the initial velocity of the particle?

If two persons sitting on a swing instead of one, why the periodic time does not changed?

Value of the rotation of point P on unit circle increase in multiple of 2pi then value of sine and cosine does not change .

…….. does not change with time for D.C. current and D.C. voltage.

A conducting ring of radius r is placed perpendicular inside a time varying magnetic field as shown in figure. The magnetic field changes with time according to B = B_0 + alphat where B_0 and alpha are positive constants. Find the electric field on the circumference of the ring.

(a) Magnetic field lines show the direction (at every point) along which a small magnetised needle aligns at the point). Do the magnetic field lines also represent the lines of force on a moving charged particle at every point? (b) Magnetic field lines can be entirely confined within the core of a toroid, but not within a straight solenoid. Why? (c) If magnetic monopoles existed, how would the Gauss's law of magnetism be modified? (d) Does a bar magnet exert a torque on itsell due to its own field? Does one element of a current-carrying wire exert a force on another element of the same wtre? (e) Magnetic field arises due to charges in motion. Can a system have magnetic moments even though its net charge is zero?

A very long wire is held vertical in a direction perpendicular to the horizontal component of Earth's magnetic field. Find the value of current to be passed through this wire so that this resultant magnetic field at a point 10 cm away from this wire becomes zero. What will be the magnetic induction at a point 10 cm away from the wire on the opposite side of this point ? Horizontal component of Earth's magnetic field H=0.36xx10^(-4)T,mu_(0)=4pixx10^(-7)Tm//A .