A charge q is enclosed by a Gaussian spherical surface of radius R. If the radius is reduced to half of R, the outward electric flux will be

A proton moving with a constant velocity passes through a region without any change in its velocity. Then in this region :

Which of the following is not a unit of electric field intensity?

A parallel beam of monochromatic light of wavelength \( 460 \text{ nm} \) passes through a long slit of width \( 0.1 \text{ mm} \). What is the angular divergence in which most of the light is diffracted ?

Read the following features of the Photoelectric effect.
(A) The maximum kinetic energy of the photoelectrons varies linearly with the frequency of incident radiation
(B) The maximum kinetic energy of the photoelectrons is dependent on its intensity.
(C) For a frequency of incident radiation, lower than the cut-off frequency, photoelectric emission is possible even if the intensity is not large.
(D) Ultraviolet light can eject photoelectrons from copper even if visible light does not eject
Choose the correct answer from the options given below:

The energy of electron in the first excited state of Hydrogen atom is -3.4 eV. The potential energy of this electron is :

The main causes of energy loss in transformers are
1. Hysteresis loss
2. Flux leakage
3. Eddy current
4. Damping
Choose the correct answer from the options given below :

Read the passage carefully and answer:
Organic compounds derived from NH3 by replacing one or more H-atoms with alkyl or aryl groups will form primary, secondary and tertiary amines. The common methods which include their preparations are reduction of nitro group, amide group and nitrile group, Gabriel phthalimide synthesis and ammonolysis of alkyl halides. Amines are basic in nature due to the presence of a lone pair of electrons on the nitrogen atom. Important chemical properties of amines include acylation, alkylation and their interaction with nitrous acid. There are various tests which can distinguish different types of amines from each other, for e.g. carbylamine test, Hinsberg's test, coupling reaction etc. Another important class of compounds which can be derived from primary amines is azo compounds. These compounds are intensely colored and widely used as dyes in textile, leather and food industries.
The final product of the following reaction is:
\(C _6 H _5 NH _2 \xrightarrow[\text { (iii) } NaNO _2 / Cu , \Delta]{\text { (i) } HNO _2}\) (ii) \(HBF _4\) ?

A long solenoid has 500 turns. When a current of 2 A is passed through it, the resulting magnetic flux linked with each turn of the solenoid is \(4 \times 10^{-3} Wb\). The self-inductance of the solenoid is

A surface with area \( \vec{S} = 20 \hat{k} \) is held in an electric field \( \vec{E} = \hat{i} + 2\hat{j} + 5\hat{k} \). The electric flux linked with the surface is

The external diameter of a 5 m long hollow copper tube is 10 cm and the wall thickness is 5 mm. If the specific resistance of copper is \( 1.7 \times 10^{-8} \text{ }\Omega\text{m} \), the resistance of the tube will be:

Which of the following matrix is not skew symmetric matrix?

Which of the following is not an alien species in India?