In the context of the formation of images by spherical mirror, which of the following statements are correct?
(A) Magnification m is +ve for real images and -ve for virtual images.
(B) f and R are -ve for a concave mirror and +ve for a convex mirror.
(C) Magnification m has no units.
(D) For a real object, u is +ve and v is +ve for real image and -ve for virtual image.
Choose the correct answer from the options given below:

A cube of side \( a \) has a charge \( Q \) at each of its vertices. What is the potential due to this charge array at the centre of the cube?

A coil when given supply of 20 V D.C. draws a current of 4 A. When the same coil is given supply of 20 V A.C. with 80 Hz, draw a current of 2 A. The self Inductance of the coil is :

A 100 W bulb working on 200 V and a 200 W bulb on 100 V, have their resistances in the ratio

A charge q is placed at the centre of a sphere of radius r. The electric flux crossing the sphere is \( \Phi \). If both the charge and radius of the sphere are doubled, the electric flux crossing the sphere will be

A positive charge is moving vertically upwards. When it enters a region of magnetic field directed towards north, the direction of force on the charge would be

A cell of emf 2.2 V gives a current of 0.2 A through a resistance of 9 \(\Omega\). The internal resistance of the cell will be:

Which of the following is/are not the characteristics of wind pollinated flowers ?
A. Light and non-sticky
B. Possess well exposed stamens
C. Large and often feathery stigma
D. Often have many ovules in each ovary.
Choose the correct answer from the options given below :

If \(\vec{a}=5 \hat{i}+\hat{j}+3 \hat{k}\) then the sum of projections of \(\vec{a}\) on \(x\)-axis, \(y\)-axis and \(z\)-axis is:

Match List-I with List-II

List-I (Type of cell/Batteries)	List-II (Reaction)
(A) Daniell cell	(I) \(2 H _2(g)+ O _2(g) \rightarrow 2 H _2 O ( l )\)
(B) Fuel Cell	(II) \(Pb ( s )+ PbO _2(s)+2 H _2 SO _4( aq ) \rightarrow 2 PbSO _4(s)+2 H _2 O ( l )\)
(C) Primary Batteries	(III) \(Zn ( s )+ Cu ^{2+}( aq ) \rightarrow Zn ^{2+}( aq )+ Cu ( s )\)
(D) Secondary Batteries	(IV) \(Zn ( Hg )+ HgO ( s ) \rightarrow ZnO ( s )+ Hg ( l )\)

Choose the correct answer from the options given below:

The ratio for the speed of the electron in the 3rd orbit of \( \text{He}^+ \) to the speed of the electron in the 3rd orbit of the hydrogen atom will be

In the depletion region of an unbiased p-n junction diode there are

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.
Which one of the following is not used as a vector in recombinant DNA
technology?