Two concentric circular loops of radii 1 cm and 20 cm are placed coaxially.
Find mutual inductance of the arrangement.

Two concentric circular loops of radii 1 cm and 20 cm are placed coaxially. If the current passed through the outer loop is changed at a rate of 5 A/ms , find the emf induced in the inner loop. Assume the magnetic field on the inner loop to be uniform.

AB and CD are respectively arcs of two concentric circles of radii 21 cm and 7 cm and centre O. If ZAOB = 30^@ , find the area of the shaded region.

Two concentric circles have radii 20 cm and 15 cm. Find the area of ring shaped region

Two circles of radii 15 cm and 8 cm touch each otherinternally. Find the circumference , area of the circle drawn on the line joining their centres as the diameter.

Two concentric circles are of radii 5 cm and 3 cm. Find the length of the chord of the larger circle which touches the smaller circle.

The area of a circle is equal to the sum of the areas of the two circles, whose radii are 5 cm and 12 cm respectively. Find the radius of the circle.

Two circular coils, one of radius r and other of radius R are placed coxially with their centres coinciding. For R >> r, obtain an expression for mutual inductance of the arrangement.

Two point charges of + 20 muC and - 80 muC are placed 18 cm apart. Find the position of the point where electric field is zero

Two lenses of focal length 10 cm and -20 cm are placed in contact .What is the total power of the combination?