Two concentric coils \(X\) and \(Y\), each of radius \(2 \pi cm\), are placed at right angles to each other. If \(X\) and \(Y\) carry 4 A and 3 A currents, respectively, then the value of the magnetic field (in \(Wb m ^{-2}\) ) at the centre of the coils is (Take \(\mu_0=4 \pi \times 10^{-7} Wb A ^{-1} m^{-1}\) )

If \(U_E=\) electric field energy density and \(U_m=\) magnetic field energy density, then

Which of the following statements are correct?
A. In a photon-particle collision number of photons are conserved.
B. The photoelectric current is directly proportional to the intensity of incident light.
C. The photoelectric emission is an instantaneous process.
D. Maximum kinetic energy of photoelectrons depend on the intensity of incident radiation.
E. The threshold frequency is different for different metals.
Choose the correct answer from the options given below:

An electron moves with a velocity of \( 1200 \, \text{m s}^{-1} \) in a magnetic field of 0.4 T at an angle of 30\(^\circ\). What will be the approximate radius of its path? (Take \( e/m \) of electron \( = 1.76 \times 10^{11} \, \text{C kg}^{-1} \))

A metallic plate exposed to white light emits electrons. The colour of light for which the stopping potential will be minimum is

Visible light of wavelength 600 nm falls normally on a single slit and diffraction pattern is obtained on a screen. It is found that the second diffraction minima is at \( \frac{\pi}{3} \). If the first minimum is obtained at \( \theta_1 \), then \( \theta_1 \) is:
Given: \( \sin 25^\circ = \frac{\sqrt{3}}{4} \)

A straight wire of mass 200 g and length 1.5 m carrying a current of 2 A is placed in a uniform magnetic field at right angles to its direction, is suspended in mid air. The magnitude of magnetic field is : \(\left(g=9.8 m / s ^2\right)\)

The unit of Productivity in terms of energy is :

Read the following passage given below and answer the question.
Production of electricity by thermal plants is not very efficient method. It is now possible to make cells in which reactants are fed continuously to the electrodes and products are also removed continuously. One of the most successful fuel cells is hydrogen fuel cell.
In hydrogen fuel cell, the reactants are bubbled through which electrodes?

From the statements given below, choose the correct statement regarding the galvanic cell.

If three year moving averages for five data items given by \(16,18,20,10,21\) are \(x, y\) and \(z\) respectively, then :

Match the coordination compounds given in List-l with the central metal atoms given in List-ll

List-I (Coordination compound)	List-II (Central metal atom)
(A) blood pigment	(I) iron
(B) chlorophyll	(II) magnesium
(C) vitamin B12	(III) rhodium
(D) wilkinson catalyst	(IV) cobalt

Choose the correct answer from the options given below:

Read the passage carefully and answer the given questions.
DNA Fingerprinting
Polymorphism in DNA sequence is the basis of genetic mapping of the human genome as well as of DNA fingerprinting. DNA fingerprinting involves identification of differences in some specific regions in the DNA sequence called repetitive DNA. It works on the principle of polymorphisms in DNA sequences. The repetitive DNA are separated from bulk genomic DNA. The bulk DNA forms a major peak and the other small peaks are referred to as satellite DNA. These repetitive/satellite DNA sequences show a high degree of polymorphisms and form the basis of DNA fingerprinting.
Which one of the following techniques is involved in DNA fingerprinting?