A pair of bullocks exerts a force of 140 N on a plough. The field being ploughed is 15 m long. How much work is done in ploughing the length of the field?

The cost of fencing a circular field at the rate of ₹ 24 per metre is ₹ 5280. The field is to be ploughed al the rate of ₹ 0.50 per m^2 . Find the cost of ploughing the field (Take pi =22/7 ).

How does the ploughing of fields help in preservation of moisture in the soil?

A circular coil of 100 turns has an effective radius of 0.05 m and carries a current of 0.1 A. How much work is required to turn it in an external magnetic field of 1.5 Wb m^-2 through 180^@ about an axis perpendicular to the magnetic field. The plane of the coil is initially perpendicular to the magnetic field.

An electric dipole consists of two opposite charges of magnitude 1 mu C (micro-coulomb) separated by a distance of 2 cm . The dipole is placed in an electric field of 10^(5) V m^(-1) .How much work must an external agent do to turn the dipole end for end , starting from a position of alignment theta = 0 ?

A field is in the shape of a trapezium having parallel sides 90 m and 30 m. These sides meet the third side at right angles. The length of the fourth side is 100 m. If it Rs. 4 costs to plough 1 m2 of the field, find the total cost of ploughing the field.

An electron beam with equivalent electric current I enters a region of crossed electric field and magnetic field B. Both the fields are uniform. It is found that the electron beam goes undeviated through the region of fields. After passing the field region, electrons hit a grounded target. How much force is exerted by the electron beam on urget? Assumem is the mass of electron and e its charge.

A field is in the form of a rectangle of length 18 m and width 15 m. A pit, 7.5 m long, 6 m broad and 0.8 m deep, is dug in a corner of the field and the earth taken out is spread over the remaining area of the field. Find out the extent to which the level of the field has been raised.

Figure shows a metal rod PQ resting on the smooth rails AB and positioned between the poles of a permanent magnet. The rails, the rod, and the magnetic field are in three mutual perpendicular directions. A galvanometer G connects the rails through a switch K. Length of the rod =15 cm, B = 0.50 T, resistance of the closed loop containing the rod = 9.0 mOmega . Assume the field to be uniform and the rod is moved with a speed of 12 cm/s. How much power is dissipated as heat in the closed circuit? What is the source of this power? :

Figure shows a metal rod PQ resting on the smooth rails AB and positioned between the poles of a permanent magnet. The rails, the rod, and the magnetic field are in three mutual perpendicular directions. A galvanometer G connects the rails through a switch K. Length of the rod =15 cm, B = 0.50 T, resistance of the closed loop containing the rod = 9.0 mOmega Assume the field to be uniform. How much power is required (by an external agent) to keep the rod moving at the same speed (= 12 cm s^-1 ) when K is closed? How much power is required when K is open? :