A current of 10 A in primary of a circuit is reduced to zero at a uniform rate in \( 10^{-3} \text{ s.} \) If coeff. of mutual inductance is 3 H, the induced emf in the secondary would be :

The figure shows a current loop having two circular arcs joined by two radial lines. If radius OA is 'a' and OD is 'b', the magnetic field at the centre O is.

Which of the following statements are correct?
A. Two major types of resistors are wire bound resistors and carbon resistors.
B. Mobility is the drift velocity per unit electric field.
C. The internal resistance of dry cells is much lower than the common electrolytic cells.
D. In electrolytic liquids, electrons carry the electric current.
E. Potentiometer is unaffected by the internal resistance of the source.
Choose the correct answer from the options given below:

\( E_1 \) and \( E_2 \) represents potential and kinetic energies of the orbital electron respectively then:

A uniformly charged infinite plane sheet of charge density \( 2 \times 10^{-8} \text{ C m}^{-2} \) is held in air.
What will be the separation between two equipotential surfaces in the region of electric field produced by the sheet, if the potential difference between them is 10 V? (\( \varepsilon_0 = 8.85 \times 10^{-12} \text{ C}^2\text{N}^{-1}\text{m}^{-2} \))

Match List-I with List-II

List-I (Physical Quantity)	List-II (Units)
(A) Magnetic field	(I) \( J \, T^{-1} \)
(B) Magnetic moment	(II) \( T \, m \, A^{-1} \)
(C) Pole strength	(III) \( J \, T^{-1} m^{-1} \)
(D) Permeability of free space	(IV) \( Wb \, m^{-2} \)

Choose the correct answer from the options given below:

A solenoid has a core of a material with a relative permeability of 500 . The windings of the solenoid are insulated from the core and carry a current of 0.5 A . If the number of turns is 2000 per metre, the magnetic intensity is

Light of two different frequencies whose photons have energies 1 eV and 2.5 eV respectively, illuminate a metal of work function 0.5 eV. The ratio of the maximum KE of the emitted electrons will be :

Match List I with List II

List-l	List-II
A. \(K _2 SO _4( aq )\) with \(60 \%\) dissociation	I. \(i = 3 . 7\)
B. \(K _3\left[ Fe ( CN )_6\right]( aq )\) with \(90 \%\) dissociation	II. \(i=1.8\)
C. \(AlCl _3( aq )\) with \(80 \%\) dissociation	III. \(i=2.2\)
D. \(K _2 HgI _4( aq )\) with \(40 \%\) dissociation	IV. \(i=3.4\)

Choose the correct answer from the options given below :

In a Young double slit experiment, if one of the slit is covered with a black paper then:

Question based on the following passage: P-Block elements are placed in group 13 to 18 in the periodic table. Group 15 is nitrogen family.
Nitrogen can react with hydrogen, oxygen, halogens etc. It shows multiple oxidation states in its various oxides i.e. \(N_2O, N_2O_3, N_2O_5\) etc. Important allotropic forms of phosphorus are white, red and black phosporus. Various compounds of phosphorus are phosphine, \(PCl_3, PCl_5\) and oxoacids of phosphorus. Oxidation states \(+1\) to \(+5\) are seen in various oxoacids of phosphorus. Group 17 elements are collectively known as halogens. Bond dissociation enthalpy of \(F_2\) is smaller than \(Cl_2\).
The gases present in group 18 are chemically unreactive, they form only few compounds. Neil Bartlett (in 1962) observed the reaction of a noble gas. Since then, many noble gas compounds have been synthesised.
Explosive nature of fluorine (\(F_2\)) is due to:

A first order reaction is found to have rate constant \(k=3.0 \times 10^{-1} \mathrm{~s}^{-1}\). The half-life of the reaction will be:

A thin lens L1 of focal length 20 cm placed in combination with another thin lens L2 acts as a lens of focal length 12.5 cm. The power of L2 is