The effective capacitance between points A and B shown in the circuit is:
If the electrical potential at a point on the surface of a hollow conducting sphere of radius R is V, then the electric potential at a point which is at a distance R/3 from the centre of the sphere is:
Two convex lenses of focal lengths 20 cm and 30 cm are placed in contact with each other co-axially. The focal length of the combination is:
A source and an observer move away from each other with same velocity of 10 m-1 with respect to the ground. If the observer finds the frequency of sound coming from the source as 1980 Hz, then the actual frequency of the source is (speed of sound in air = 340 ms-1)
A cylinder of mass m and material density ρ hanging from a string is lowered into a vessel of cross - sectional area A containing a liquid of density σ (< ρ) until it is fully immersed. The increase in pressure at the bottom of the vessel is: