The resistivity of a conductor in which a current density of \( 3.5 \, \text{A m}^{-2} \) is found to exist on applying an electric field of \( 28 \, \text{V m}^{-1} \) will be:

A plane electromagnetic wave travels in vacuum along y-direction. At the same instant, the direction of Electric and magnetic fields are:

If \( \lambda_1 \) and \( \lambda_2 \) are the longest wavelengths of the Lyman and Paschen series respectively, then \( \lambda_1 : \lambda_2 \) is:

Which of the following is NOT a property of charges?

When a metal rod of length L placed normal to a uniform magnetic field B is moved at a velocity of v perpendicular to the field, the induced emf across its ends is

Identify the incorrect statements from the following.
(A) A charged particle of charge e is moving through a magnetic field, work will be done by the magnetic field on the charge.
(B) A conductor with free electrons is placed in a magnetic field. No current is flowing through the conductor. No magnetic force acts on the conductor.
(C) A charged particle is moving perpendicular to the magnetic field. The magnetic force does not change the speed of the particle but changes its direction.
(D) A charged particle is moving in a straight direction without any change of direction. It shows that no magnetic field is there.
Choose the correct answer from the options given below:

A freshly prepared radioactive sample of half life 1 hour emits radiations that are 128 times as intense as the permissible safe limit. What is the minimum time after which the sample can be safely used?

The solubility of the gas in a liquid :
(A) Increases with increase in pressure
(B) Decreases with increase in pressure
(C) Increases with increase in temperature
(D) Decreases with increase in temperature
Choose the correct answer from the options given below :

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.

The reaction is an example of:

In a survey of a sample of 300 individuals, 180 gave response 'Yes',
100 gave response 'No' and 20 gave `No response'
Find the point estimate of proportion in the population who responded 'Yes'

Which statement is not true for a detergent molecule ?

A point charge is placed at any point on the axis of an electric dipole at some large distance, experiences a force F. The force acting on the point charge when it's distance from the dipole is halved will be

The magnetic flux linked with a coil at any instant t is given by \( \Phi = (4t^3 - 3t^2 + 2t + 5) \text{ Wb} \). The emf induced in the coil at \( t = 3 \text{ s} \) is