A transistor is operated in common emitter configuration at \(V_c = 3V\) such that a change in the base current from \(50 \mu A\) to \(250 \mu A\) produces a change in the collector current from 5 mA to 20 mA. The current gain is :

A steady current flows in a conductor of non-uniform cross-section. The physical quantity which remains constant along the length is :

The current sensitivity of a moving coil galvanometer can be increased by
A. Decreasing the magnetic field
B. Increasing the number of turns
C. Increasing the area of the coil
D. Inserting a soft iron core in the coil
E. Decreasing the area of the coil
Choose the correct answer from the options given below:

Electromagnetic waves carry

Three resistances of magnitude \(2 \Omega\), \(3 \Omega\) and \(5 \Omega\) are connected in parallel to a battery of 10 V and of negligible resistance. The potential difference across \(3 \Omega\) resistance will be:

An electron revolves around a very long line charge having density \( 2 \times 10^{-6} \, Cm^{-1} \). The kinetic energy of the electron is

A neutron is absorbed by a \( {}^6_3\text{Li} \) nucleus with subsequent emission of an alpha particle. The energy released in the reaction is
Use mass of \( {}^6_3\text{Li} = 6.015126 \text{ u} \)
Mass of \( {}^4_2\text{He} = 4.002604 \text{ u} \)
Mass of \( {}^1_0\text{n} = 1.008665 \text{ u} \)
Mass of \( {}^3_1\text{H} = 3.016049 \text{ u} \) and \( 1 \text{ u} = 931 \text{ MeV} \)

Which of the following is incorrect about chemical adsorption ?

Answer the question on basis of passage given below :
Alcohols and phenol are formed when a hydrogen atom in a hydrocarbon, aliphatic and aromatic respectively, is replaced by \(\text{-OH}\) group. The substitution of a hydrogen atom in a hydrocarbon by an alkoxy or aryloxy group forms ethers. Alcohols and phenol consist of two part, an alkyl/aryl group and a hydroxyl group. The properties of alcohols and phenols are primarily due to the hydroxyl group. The nature of alkyl and aryl groups simply modify these properties. Alcohol react both as nucleophiles and electrophiles whereas in phenols, the reactions that take place on the aromatic ring are electrophilic subtitution reactions.
Aspirin is an acetylation product of :

In a series LR circuit, the inductive reactance is equal to the resistance R of the circuit. An emf \( E = E_0 \cos \omega t \) is applied to the circuit. The average power dissipated in one cycle is :

The electrochemical cells \(Zn \left| Zn ^{2+} \| Cu ^{2+}\right| Cu\) and \(Fe ^{-} Fe ^{2+} \| Cu ^{2+} \mid Cu\) are connected in series. What will be the net emf of the cell at \(25^{\circ} C\) ? Given: \(E ^{\circ}\) of \(Zn ^{2+} \mid Zn =-0.76 V ; \quad E ^{\circ}\) of \(Cu ^{2+} \mid Cu =+0.34 V ; \quad E ^{\circ}\) of \(Fe ^{2+} \mid Fe =-0.41 V\)

Let \(A=\left[a_{i j}\right]\) be a square matrix of order 3 with each entry either 0 or 1 .
Then the number of all such possible matrices is :

Let \(f\) be a function defined by \(f(x)=2 x^3-3 x^2-36 x+2\), then which of the following are correct ?
(A) The critical points of \(f ( x )\) are \(- 2\) and 3 .
(B) The function \(f(x)\) increases in the interval \((3, \infty)\)
(C) The function \(f(x)\) decreases in the interval \((-2,3)\)
(D) The function \(f(x)\) increases in the interval \((-2,3)\)
Choose the correct answer from the options given below :