Physics

A uniform wire of resistance $R$ is stretched uniformly to $n$ times. It is then cut to form five wires of equal length. These wires are arranged as shown in figure. the effective resistance between $A$ and $C$  is

The surface are frictionless, the ratio of T$$ l and $T_2$ ${}_{}$ is 

An electric bulb and a capacitor are connected in series with an AC source. On increasing the frequency of the source, the brightness of the bulb:

A direct current of 4 A and an alternating current of 4 A flows through two identical resistors. The ratio of heat produced in the two resistances in same time interval will be

An electromagnetic wave propagates in a medium, whose electric field vector is given as E = 200sin (18 * 10⁸t + 8x) V m^-1. Retractive index of medium and amplitude of magnetic field will be

ISRO observed the wavelength of sodium line emitted by a star is 589.6 nm. The actual wavelength emitted by star is 589 nm. The speed of the star with respect to us would be

Suppose the gravitational force varies inversely as the $n^{th}$ power of distance. Then, time period of a planet in circular orbit of radius R around the sum will be proportional to

Magnetic flux through a closed conducting loop of resistance   $4\Omega$ changes with time as $?=\left(2t^2+8t+6\right)$  Wb, where t is time in seconds. The heat produced from t = 0 to t = 2 s is   

A metal wire of uniform mass is used as simple pendulum. If the temperature of metal wire is increases by   $10°C$ and coefficient of linear expansion of the wire is 2 * 10^-6   $°C^{-1},$ the time period of pendulum will increase by

The equation of a wave traveling on a string is y = 10sin $\left[\pi \left(5t-\frac{x}{4}\right)\right],$  where x, y are in cm and t is in second. The velocity of wave is