According to Bohr's theory, the angular momentum of an electron revolving in the second orbit of the hydrogen atom will be:

What will be the half life of a radioactive isotope whose \(\left(\frac{1}{16}\right)^{\text {th }}\) of initial amount remains unchanged after 2 hours ?

Three charges of magnitude \( -2Q, -3Q \) and \( Q \) are located at \( (a, 0, 0), (3a, 0, 0) \) and \( (5a, 0, 0) \) respectively. What is the magnitude of electric flux due to these charges through a sphere of radius 4a with its centre at the origin?

Which of the following is necessary to use to achieve half wave rectification of an alternating current?

Choose the correct phase relationship between the current and the applied voltage in an a.c. circuit.
(A) In a pure resistive circuit, the current is in phase with the applied voltage.
(B) In a pure inductive circuit, the current lags behind the voltage by a phase angle of 90°.
(C) In a pure inductive circuit, the current leads the voltage by a phase angle of 90°.
(D) In a pure resistive circuit, the current is not in phase with the applied voltage.
Choose the correct answer from the options given below:

In a semiconductor, there are :
(A) no free electrons at any temperature
(B) no free electrons at 0 K
(C) number of free electrons increase with temperature
(D) number of free electrons decrease with temperature
Choose the correct answer from the options given below:

In a common emitter amplifier the audio signal voltage across the collector resistance of 2 \( k\Omega \) is 2 V. The current amplification factor is 50. The value of base current is:

Statins produced by the yeast variety is _______ which have been commercialised as blood-cholesterol lowering agents.

Read the passage carefully and answer the Questions:
Amines are classified as primary \(\left(1^{\circ}\right)\), secondary \(\left(2^{\circ}\right)\) and tertiary \(\left(3^{\circ}\right)\) depending upon the number of hydrogen atoms replaced by alkyl or aryl groups in ammonia molecules. Aliphatic amines are a stronger bases due to \(+I\) effect of an alkyl groups. Intermolecular hydrogen bonding in primary and secondary amines affects the boiling points of amines. The intermolecular association is more in primary amines than in secondary amines as there are more number of hydrogen atoms available for hydrogen bond formation. Nitro compounds are reduced to amines by passing hydrogen gas in the presence of finely divided nickel, palladium or platinum and also by reduction with metals in an acidic medium. Gabriel synthesis is used for the preparation of primary amines. Primary amines react with nitrous acid to give unstable diazonium-salts which can be used to synthesize a variety of compounds.
Identify the amine possessing least basic strength:

If \((x+1) e^y=1\), then :

When the electron in a hydrogen atom jumps from the 2nd orbit to the 1st orbit, the wavelength of the radiation emitted is \(\lambda\).
When the electron jumps from the 3rd orbit to the 1st orbit, the wavelength of emitted radiation is:

The particular solution of the differential equation \(\left\{x \sin ^2\left(\frac{y}{x}\right)-y\right\} d x+x d y=0, y=\frac{\pi}{4}\) when \(x=1\) is

When a number of capacitors are connected in parallel between two points increases, the equivalent capacitance