A proton is moving in a circular path in a magnetic field perpendicular to its plane. It possesses kinetic energy E. If the magnetic field increases to four times and the proton moves in same circular path, what will be kinetic energy?

Which of the following statements are correct?
(A) All of electrostatics is basically a consequence of Coulomb's law and the super position principle.
(B) A change producing the electric field is a test change.
(C) Electric and magnetic fields are regarded as physical entities.
(D) In water molecule centres of positive changes and negative changes do not coincide.
(E) Electrostatic field lines cannot form closed loops.
Choose the correct answer from the options given below :

A slit of width 'd' is illuminated by red light of wavelength 650 nm. What should be the value of slit width 'd' so that first minimum fall at an angle of diffraction of \(\frac{\pi}{6}\) ?

A plane E-M wave of frequency 48 MHz travels in free space along the positive x-direction. At a particular point in space and time \( \vec{E} = 10.2\hat{j} \text{ V/m} \). The corresponding magnetic field \( \vec{B} \) at that point will be:

In a p-n junction, the magnitude of the drift current is lower than the magnitude of the diffusion current when the junction is

Which is quantised in Bohr's atomic model ?

Which of the following combinations should be used for better tuning of an LCR circuit used for communication?

Antibiotic, which is bacteriostatic among the following is:

'Statins', are produced by which of the following microbe?

The varieties of rice in India which are one of the richest in the world, they are approximately:

Which of the following compounds will give the Hell-Volhard-Zelinsky reaction?

Read the passage carefully and answer the questions
Amines are considered as derivatives of ammonia obtained by replacement of hydrogen atoms with alkyl or aryl groups. In nature they occur among proteins, vitamins, alkaloids and hormones. These can be primary, secondary or tertiary depending on the number of hydrogen groups replaced. They can be prepared from nitro compounds, alkyl halides, nitriles, amides etc. Due to unshared pair of electrons they behave as Lewis bases. Influence of the number of hydrogen atoms at nitrogen atom is displayed in physical properties such as solubility, boiling point and chemical reactions including basicity. Basic character of amines is expressed in terms of their \(K_b\) and \(p K_b\) values. Three classes of amines can be distinguished with p-toluene sulphonyl chloride which reacts with primary and secondary ddu amines. Amino group when attached to benzene ring behaves as an activating and ortho para directing group.
Which reagent is used for the conversion of acetamide into ethylamine?

Two identical metal balls, A and B, with similar charges Q are suspended with insulating threads. They repel each other with a force F. Another identical uncharged metal ball C is first touched with metal ball A and then touched with metal ball B and finally removed. The new force of repulsion between A and B will be