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

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 :

Two buses P and Q start from a point at the same time and move in a straight line and their positions are represented by X_p(t) = αt+ βt² and X_Q(t) =ft - t². At what time, both the buses have same velocity?

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 ______. 

A conducting wire has length 'L₁' and diameter 'd₁'. After stretching the same wire length becomes 'L₂' and diameter 'd₂' The ratio of resistances before and after stretching is ______.

The energy of an electron having de-Broglie wavelength `λ` is ______.

(h = Plank's constant, m = mass of electron)

Two unknown resistances are connected in two gaps of a meter-bridge. The null point is obtained at 40 cm from left end. A 30 Ω resistance is connected in series with the smaller of the two resistances, the null point shifts by 20 cm to the right end. The value of smaller resistance Ω is ______.

In series LCR circuit R = 18 Ω and impedance is 33 Ω An rms voltage 220V is applied across the circuit. The ture power consumed in AC circuit is ______.

For a transistor,  α_dc and β_dc are the current ratios, then the value of `(beta_"dc"-delta_"dc")/(alpha_"dc".beta_"dc")` 

An electron of mass m has de-Broglie wavelength λ when accelerated through potential difference V. When proton of mass M, is accelerated through potential difference 9V, the de-Broglie wavelength associated with it will be ______. (Assume that wavelength is determined at low voltage)

The ratio of the forces between two charges placed at a certain distance apart in the air and by the same distance apart in a medium of dielectric constant K is ______.

Two point charges +2 C and +6 C repel each other with a force of 12 N. If a charge of -4 C is given to each of these charges, then the force now is ______.

In a p-n-p transistor circuit, the collector current is 10 mA. If 90% of the holes emitted from the emitter reach the collector, ______.