Semiconductor Electronics: Materials, Devices and Simple Circuits — Physics STD 12 Science — Question

A primary cell has an e.m.f. of 1.5 volts, when short-circuited it gives a current of 3 amperes. The internal resistance of the cell is(a) 4.5 ohm (b) 2 ohm(c) 0.5 ohm(d) 1/4.5 ohm

Half life of a radioactive element is 10 days. The time during which quantity remains 1/10 of initial mass will be(a) 100 days(b) 50 days(c) 33 days(d) 16 days

Rutherford’s atomic model was unstable because:

Which of the following is most suitable for the core of electromagnets(a) Soft iron(b) Steel(c) Copper-nickel alloy(d) Air

An air capacitor is connected to a battery. The effect of filling the space between the plates with a dielectric is to increase(a) The charge and the potential difference(b) The potential difference and the electric field(c) The electric field and the capacitance(d) The charge and the capacitance

Ionisation energy of 10 times ionised sodium atom will be :

In Fresnel’s biprism (μ  = 1.5) experiment the distance between source and biprism is 0.3 m  and that between biprism and screen is 0.7m and angle of prism is 1°. The fringe width with light of wavelength 6000 Å will be(a)  3 cm(b) 0.011 cm(c) 2 cm  (d)  4 cm

In case of a bar magnet, lines of magnetic induction: