Physics

Consider a p-n junction diode which has a potential drop of 0.5 V which is to be taken independent of current (under forward bias). If we want to use 1.5 V cell to forward bias the diode then what should be the value of resister (in Ω) used in series with the diode so that current may not exceed 10 mA, and hence may work safely.

A carnot engine works between temperatures 327°C and 27°C. If the engine takes 1600 J of heat from the higher temperature reservoir, the work done by the engine per cycle (in Joule) is equal to ______.

The fundamental frequency of an organ pipe open at one end is 300 Hz. The frequency of 3rd overtone of n Find n.*this organ pipe is 100 Hz

In the colour coding system of carbon resistors, the tolerance (in %) shown by gold band is ____.

A radioactive sample decays with a constant of (1/3)logₑ2 s⁻¹. If initially there are 200 nuclei present, find the number of nuclei decayed during the first 9 seconds.

Two fixed long parallel horizontal rails, a distance 1 m apart are joined at one end by a resistance 1Ω . A rod AB of negligible resistance slides towards the resistance. A magnetic field of magnitude 4T perpendicular to the plane of rails exists. Find the current flowing (in Ampere) in the resistance, at an instant when the velocity of the rod is 2 m/s.

If the molar specific heat at constant pressure for a polyatomic non-linear gas is x and the molar specific heat at constant volume for a diatomic gas is y, find the value of x y

A plank of mass 5 kg in kept on a smooth surface. A block of 1 kg is kept on it and is given a velcoity of 12 m/s. There is friction between the block and the plank. Assuming the plank to be very long, find the magnitude of work done (in Joules) by friction on block till the relative sliding between them stops.

Two capacitros are fully charged by a battery as shown in the figure.

If the capacitors are disconnected from battery and plate 1 is connected to plate 4 & plate 2 to plate 3, then find the potential difference (in volts) across capacitors finally.

When monochromatic light of wavelength 620 nm is used to illuminate a metallic surface, the maximum kinetic energy of photoelectrons emitted is 1 eV. Find the maximum kinetic energy of photoelectron emitted (in eV) if a wavelength of 155 nm is used on the same metallic surface. (hc = 1240 eV-nm)