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Practice Online Test Series for JEE Main 2018 & NEET 2018
In a P-N -P transistor, the collector current is 10 mA. It 90% of the holes reach the collector, then emitter current will be:
A transistor has a base current of 1 mA and emitter current 100 mA. The current transfer ratio will be
When the base-emitter voltage of a transisitor connected in the common-emitter mode is changed by 20 mV the collector current is changed by 25 mA. Find the transconductance.
In a transistor circuit the base current changes from `30muA` to `90muA` .If the current gain of the transistor is 30, the change in the collector current is
For a common base amplifier, the values of resistance gain and voltage gain are 3000 and 2800 respectively. The current gain will be
If A + B + 1, then in terms of Boolean algebra the value of A.B + A is not equal to
In the Binary number system 1 + 1 =
A p- n junction diode has breakdown voltage of 28 V. If applied external voltage in reverse bias is 40 V the current through it is
The value of current in the following diagrams is (diode assumed to be ideal one)
Two identical p-n junctions may be connected in series with a battery in three ways. The potential drops across the two p-n junctions are equal in:
The output Y, when all the three inputs are first high and then low, will respectively be:
An AND gate is followed by a NOT gate in series. With two inputs A and B, the Boolean expression for the output Y will be
A pure Ge specimen is doped with A1. The number density of acceptor atoms is approximately `10^21 m^(-3)`. If density of electron hole pair in an intrinsic semiconductor is approximately `10^19 m^-3`, the number density of electrons in the speciment is:
In the following common emitter circuit if `beta = 100, V_(CE) = 7V, V_(BE)=`negligible, `R_c = 2k Omega` then
`I_B=?`
If in a p-n junction diode, a square input of 10 v is applied as shown:
Then, the output signal across `R_L` will be:
What could be a correct expression for the speed of ocean waves in terms of its wavelength `lambda` the depth h of the ocean, the density `rho` of sea water, and the acceleration of free fall g?
A uniform meter scale is supported from its 20 cm mark. A body suspended from 10 cm mark keeps the scale horizontal. However, the scale gets unbalanced if the body is completely immersed in water. To regain the balance the body is shifted to the 8 cm mark. Therefore, the specific gravity of the material of the body is:
A surface of area S is placed perpendicular to the direction of travel of a plane wave. The energy per unit time intercepted by the surface is E when the amplitude of the wave is A. The area of the surface is reduced to `1/2` S and the amplitude of the wave is increased to 2A. What is the energy per unit time intercepted by this smaller surface?
A 40 g ball dropped from a certain height bounces back from the horizontal ground without losing mechanical energy. If its speed is 10 m/s just before making contact with the ground, and the average value of the force of the ground on the ball is equal to 16N while ball and wall are in contact, how long were they in contact?
If the threshold of hearing is assumed to be the reference (0 dB), then the threshold of pain is taken to be 120 dB. Lets the corresponding sound intensities be `I_o` and I respectively. Then, `I_o/I` is:
