The intensity of a plane monochromatic wave is \( 1380 \text{ Wm}^{-2} \). What is the amplitude of electric field in this wave ? (Take speed of light \( 3 \times 10^{8} \text{ ms}^{-1} \); \( \epsilon_{0} = 8.85 \times 10^{-12} \text{ C}^{2}\text{N}^{-1}\text{m}^{-2} \))

A long solenoid with 30 turns/cm has a small loop of area \( 3 \text{ cm}^2 \) placed inside it normal to its axis. If the current in the solenoid changes steadily from 3.0 A to 6.0 A in 0.1 s, the induced emf in the loop is :

Two lenses of focal lengths, 20 cm and - 25 cm, respectively are placed in contact with each other. The power of the combination of lenses is

Two nuclei have their mass numbers in the ratio of \(1: 3\). The ratio of their nuclear densities would be :

The capacitance of capacitor increases when :
(A) its charge increases
(B) its supply voltage decreases
(C) common area of the plates increases
(D) separation between the plates decreases
Choose the correct answer

The dipole moment of a circular loop carrying a current I is m and the magnetic field at the centre of the loop is \( B_1 \). When the dipole moment is made three times by keeping the current I same, the magnetic field at the centre of the loop becomes \( B_2 \). The ratio of \( B_1 \) and \( B_2 \) is:

A wire of resistance \( 5\Omega \) is drawn out so that its length is increased by thrice its original length. The new resistance would be :

Match List-I with List-II

List-I	List-II
(A) Acetone to secondary alcohol	(I) \(CrO _3\)
(B) Ethanol to Diethyl ether	(II) \(Zn\)
(C) Ethanol to ethanal	(III) \(NaBH _4\)
(D) Phenol to Benzene	(Iv) \(H _2 SO _4\) at 413 K

Choose the correct answer from the options given below :

A is a \(2 \times 2\) non-singular matrix such that adj \(A=\left[\begin{array}{cc}\sin \theta-\cos \theta & -\sin \theta \sec \theta \\ 2 \cos ^2 \theta & \sin \theta-\cos \theta\end{array}\right]\) then \(|A|\) is:

A galvanometer of resistance \(76 \Omega\) gives full scale deflection when only \(5 \%\) of total current passes through it. The value of shunt is :

Read the passage carefully and answer the given questions.
Recombinant DNA Technology Asexual reproduction preserves the genetic information, while sexual reproduction permits variation. Traditional hybridization procedures used in plants and animals breeding very often lead to inclusion and multiplication of undesirable genes along with the desired genes. The techniques of genetic engineering, which include creation of recombinant DNA, use of gene cloning and gene transfer, overcome this limitation and allow us to isolate and introduce only one or a set of desirable genes without introducing genes into the target organism.
In Recombinant DNA Technology, what is the role of the "selectable marker gene"?

Choose the correct statement regarding dependence of electric potential at a point due to an electric dipole:

The increased resistance of a wire if its length is doubled and the original cross-sectional area is halved will be: (Given \(R=\) original resistance of the wire)