A wire $$P Q$$ has length $$4.8 \mathrm{~m}$$ and mass $$0.06 \mathrm{~kg}$$. Another wire QR has length $$2.56 \mathrm{~m}$$ and mass $$0.2 \mathrm{~kg}$$. Both wires have same radii and are joined as a single wire. This wire is under tension of $$80 \mathrm{~N}$$. A wave pulse of amplitude $$3.5 \mathrm{~cm}$$ is sent along the wire $$\mathrm{PQ}$$ from end $$\mathrm{P}$$. the time taken by the wave pulse to travel along the wire from point P to R is ?

When a monochromatic ray of light is passed through an equilateral glass prism, it is found that the refracted ray in glass is parallel to the base of the prism. If '$$i$$' and '$$e$$' denote the angles of incidence and emergence respectively, then

A solid cylinder and a solid sphere having same mass and same radius roll down on the same inclined plane. The ratio of the acceleration of the cylinder '$$a_c$$' to that of sphere '$$a_s$$' is

An alternating voltage $$E=200 \sqrt{2} \sin (100 t)$$ volt is connected to a $$1 \mu \mathrm{f}$$ capacitor through an a.c. ammeter. The reading of the ammeter shall