Semiconductor Electronic: Material, Devices And Simple Circuits — Physics STD 12 Science — Question

The spectral series of the hydrogen spectrum that lies in the ultraviolet region is the

(a) Balmer series

(b) Pfund series

(c) Paschen series

(d) Lyman series

The reciprocal of resistance is

(a) Conductance

(b) Resistivity

(c) Voltage

(d) None of the above

In a beryllium atom, if a₀ be the radius of the first orbit, then the radius of the second orbit will be in general

(a)

(b)

(c)

(d)

An unknown hot gas emits radiation of wavelengths 46.0nm, 82.8nm and 103.5nm only. Assume that the atoms have only two excited states and the difference between consecutive energy levels decreases as energy is increased. Taking the energy of the highest energy state to be zero, find the energies of the ground state and the first excited state.

Which of the following figures correctly shows the phase relation between the input signal and the output signal of triode amplifier

(a)	(b)
(c)	(d)

Figure (i) shows a conducting loop being pulled out of a magnetic field with a speed v. Which of the four plots shown in figure (ii) may represent the power delivered by the pulling agent as a function of the speed v

(a) a

(b) b

(c) c

(d) d

If in a nuclear fusion process the masses of the fusing nuclei be  and   and the mass of the resultant nucleus be , then

(a)

(b)

(c)

(d)

In Young’s double slit experiment the wavelength of light was changed from 7000 Å to 3500 Å. While doubling the separation between the slits which of the following is not true for this experiment

(a) The width of the fringes changes

(b) The colour of bright fringes changes

(c) The separation between successive bright fringes changes

(d) The separation between successive dark fringes remains unchanged

If the strength of the magnetic field produced 10cm away from a infinitely long straight conductor is  , the value of the current flowing in the conductor will be

(a) 5 ampere

(b) 10 ampere

(c) 500 ampere

(d) 1000 ampere

Two insulated charged spheres of radii 20 cm and 25 cm respectively and having an equal charge Q are connected by a copper wire, then they are separated

(a) Both the spheres will have the same charge Q

(b) Charge on the 20 cm  sphere will be greater than that on the 25 cm  sphere

(c) Charge on the 25 cm  sphere will be greater than that on the 20 cm  sphere

(d) Charge on each of the sphere will be 2Q