MAH-MHT CET (PCM/PCB) entrance exam Question Bank Solutions for Physics

In a transistor, doping level in base is increased slightly, the collector current and base current respectively ______.

In transistor amplifier, base-emitter junction is forward biased and collector emitter junction is reverse biased. The current gain is ______.

In the case of transistor, the relation between current ratios α_dc and β_dc is ______.

In common emitter mode of transistor, the d.c. current gain is 20, the emitter current is 7 mA. The collector current is ______.

A change of 9.0 mA in the emitter current brings a change of 8.9 mA in the collector current. The value of current gain β will be ______.

A transistor is connected in C - E mode. If collector current is 72 × 10^-5 A and α = 0.96, then base current will be ______.

An e.m.f. E = E₀ sin `omega`t is applied to a circuit containing 'L' and 'R' in series. If X_L = R, then the power dissipated in the circuit is ____________.

According to de-Broglie hypothesis, the ratio of wavelength of an electron and that of photon having same energy 'E' is (m = mass of electron, c = velocity of light) ____________.

The voltage gain of a CE amplifier is 50. A sinusoidal ac of amplitude 10 mV is applied as a signal. The output of the amplifier will be ______.

A photon of wavelength 3315 Å falls on a photocathode and an electron of energy 3 x 10^-19 J is ejected. The threshold wavelength of photon is [Planck's constant (h) = 6.63 x 10^-34 J.s, velocity of light (c) = 3 x 10⁸ m/s] ____________.

The ratio of the forces between two small spheres with constant charge (a) in air (b) in a medium of dielectric constant K is ______.

For an ideal diode, the current in the following arrangement is ______.

In common emitter amplifier, a change of 0.2 mA in the base current causes a change of 5 mA in the collector current. If input resistance is 2K `Omega` and voltage gain is 75, the load resistance used in the circuit is ______.

In a study of transistor as an amplifier, the ratio of collector current to emitter current is 0.98. The collector current is 3mA, then base current will be approximately ______.

A transistor having α = 0.8 is connected in a common emitter configuration. When the base current changes by 6 mA, the change in collector current is ______ 

In the common-emitter configuration of a transistor, the current gain is more than 1 because [l_b, l_e, and l_c are base, emitter, and collector currents respectively] ______

A proton, a neutron, an electron and an α-particle have same energy. λ_p, λ_n, λ_e and λ_α are the de Broglie's wavelengths of proton, neutron, electron and α particle respectively, then choose the correct relation from the following :

In a series LR circuit X_L = R and power factor of the circuit is P₁. When capacitor with capacitance C such that X_L= X_C is put in series, the power factor becomes P₂. The ratio `"P"_1/"P"_2` is ______. 

A common emitter amplifier has a voltage gain of 50, an input impedance of 100Ω and an output impedance of 2000Ω. The power gain of the amplifier is ______.

A transistor is used as a common emitter amplifier with a load resistance 2 KΩ. The input resistance is 150 Ω. Base current is changed by 20 µA which results in a change in collector current by 1.5 mA. The voltage gain of the amplifier is ______.