Which of the following statements are correct?
A. Dipole field depends on the distance r and also on the angle between the position vector and the dipole moment P
B. A comb runs through dry hair acquires charge through friction
C. If surface charge density of a plate is positive, the electric field is directed towards the plate.
D. Electrostatic field lines cannot form closed loops.
E. In a uniform electric field, a dipole experiences a torque and a net force also.
Choose the correct answer from the options given below:

An object is placed before a convex lens and its real image is obtained. Now if half of the surface is covered with paper. The result will be :

A parallel plate capacitor whose capacitance C is 13.0 pF is charged by a battery to a potential difference V = 13.0 V between its plates. What is the potential energy of the capacitor ?

Current carrying wire produces:

The number of free electrons per 100 mm of ordinary copper wire is 2 \(\times 10^{21}\). The average drift speed of electrons is 0.25 mm/s. The amount of current flowing would be : (e = 1.6 \(\times 10^{-19}\) C)

The forbidden energy gap for Si is

If the wave length of 1st line of Balmer series of hydrogen is 6561A, the wavelength of the 2nd line of series will be:

Two cards are drawn simultaneously at random from a well shuffled pack of 52 Cards.
Let X be the random variable which denotes number of kings in the draw. Then the probability distribution of X is

Read the passage carefully and answer the questions given along
Our immune system plays the major role in preventing diseases when we are exposed to disease-causing agents. Immunity is of two types: (i) Innate immunity and (ii) Acquired immunity. The human immune system consists of lymphoid organs, tissues, cells and soluble molecules like antibodies. The immune system also plays an important role in allergic reactions, auto-immune diseases and organ transplantation. The primary lymphoid organs are bone marrow and thymus. The secondary lymphoid organs are spleen, lymph nodes, tonsils, Peyer's patches of small intestine and appendix. There is lymphoid tissue also located within the lining of the major tracts (respiratory, digestive and urogenital tracts) called mucosa associated lymphoid tissue (MALT). It is important to note that HIV/AIDS is not spread by mere touch or physical contact; it spreads only through body fluids. AIDS has no cure, prevention is the best option. Adolescence is accompanied by several biological and behavioural changes and surveys and statistics show that use of drugs and alcohol has been on the rise especially among the youth. Factors associated with drug and alcohol abuse among adolescents are a child's natural curiosity, stress, the perception among youth that it is 'cool' or progressive to smoke, media exposure and an unstable or unsupportive family structures and peer pressure. It is best to identify the situations that may push an adolescent towards use of drugs or alcohol, and to take remedial measures well in time.
Find the incorrect statement about human health and disease.

Read the following passage carefully.
Restriction enzyme
Restriction enzymes cut the strand of DNA a little away from the center of the palindrome sites, but between the same two bases on the opposite strands. This leaves single stranded portions at the ends. There are overhanging stretches called sticky ends on each strand. These are named so because they form hydrogen bonds with their complementary cut counterparts. This stickiness of the ends facilitates the action of the enzyme DNA ligase. The word palindromes refer to group of letters that forms the same words when read both forward and backward. Restriction endonucleases are used in genetic engineering as molecular scissors.
Palindromes are:

Match the property given in List-l with the element given in List-Il

List-I (Property)	List-ll (Element)
(A) Lanthanoid, which can show +2 oxidation state	(I) Pm
(B) Radioactive lanthanoid	(II) Lu
(C) Lanthanoid which has \(4 f^{\wedge} 7\) electronic configuration in +3 oxidation state	(III) Eu
(D) Lanthanoid which has \(4 f^{\wedge}\{14\}\) electronic configuration in +3 oxidation state	(IV) Gd

Choose the correct answer from the options given below:

If \(\hat{a}, \hat{b}\) and \(\hat{c}\) are three units vectors and \(\hat{a}+\hat{b}+\hat{c}=\overrightarrow{0}\), then the angle between \(\hat{a}\) and ( \(-\hat{b}\) ) is

The minimum energy required to excite a Hydrogen atom from its ground state is :