Two identical charged produces moving with the same speed enter a region of uniform magnetic field. If one of these enters normal to the field direction and the other enters along a direction at 30° with the field. What would be the ratio of their angular frequencies.

A long straight wire AB carries a current I. A proton P travels with a speed v, parallel to the wire, at a distance d from it in a direction opposite to the current as shown in figure what is the force experienced by the proton and what is its direction?

Can a galvanometer be used for measuring the current? Explain.

A given galvanometer is to be converted into
(i) an ammeter
(ii) a voltmeter.
In which case will the required resistance be
(i) least
(ii) highest and why?

State the rule which is used to find the direction of field acting at a point near a current carrying street conductors?