A capillary tube is attached horizontally to a constant heat arrangement. If the radius of the capillary tube is increased by 25%, then the rate of flow of liquid will change nearly by
In the arrangement shown in figure, when the switch S2 is open, the galvanometer, shows no deflection for $$l$$ = 50 cm when the switch S2 is closed, the galvanometer shows no deflection for $$l$$ = 0.416 m. The internal resistance (r) of 6 V cell is
In a young's double slit arrangement fringes are produced using light of wavelength 4000 $$\mathop A\limits^o $$. One slit is covered by a thin plate of glass of refractive index 1.4 and the other with another glass plate of same thickness but of refractive index 1.7. By doing so the central bright shifts to original sixth fringe from centre. Thickness of glass plate is ................. .
An electric current I enters and leaves a uniform circular wire of radius r through diametrically opposite points. A charged particle q moves along the axis of circular wire passes through its centre at speed v. The magnetic force on the particle when it passes through the centre has a magnitude.