Energy gap between valence band and conduction band of a semiconductor is approximately :

A pure inductor of 70 mH is connected to a source of 220 V. The frequency of the source is 50 Hz. The current in the circuit is:

Which of the following frequencies will be suitable for beyond-the-horizon communication using sky waves?

Biot-Savart law indicates that the moving electrons (velocity \(\vec{v}\)) produce a magnetic field \(\vec{B}\) such that:

Match List-I with List-II:

List-I (Physical quantity)	List-II (Unit)
(A) Magnetic moment	(I) N A\(^{-2}\)
(B) Magnetic field strength	(II) N m rad\(^{-1}\)
(C) Torsion constant	(III) A m\(^{-1}\)
(D) Magnetic permeability	(IV) A m\(^2\)

choose the correct answer from the options given below:

Two charges \( q_1 = 4 \times 10^{-7} \text{ C} \) and \( q_2 = -6 \times 10^{-7} \text{ C} \) are located 3 m apart. At what point on the line joining the two charges is the electric potential zero? (Consider potential zero at infinity.)

Conditions for obtaining a interference pattern of light are
(A) Two waves should be coherent
(B) The distance of the screen from the slits should be small
(C) The separation between slits should be small
(D) Two coherent waves should have nearly the same amplitude
Choose the correct answer from the options given below:

When \(Br_2\) is treated with aqueous solution of \(NaF, NaCl, NaI\) separately:

A person has taken a loan of Rs. 40, 000 for 3 months from a lender who has deducted Rs. 2, 000 as interest at the time of lending.
Then the effective rate of interest charged per annum by the lender is :
[Given \((1.0526)^4=1.2275\) ]

If \(A=\left[\begin{array}{ccc}2 & 1 & 3 \\ 4 & -3 & 5\end{array}\right]\) and \(B=\left[\begin{array}{cc}-2 & 3 \\ 4 & -5 \\ 1 & 2\end{array}\right]\), then which of the following statements are TRUE?
(A) AB is defined
(B) AB and BA both are defined and \(A B=I\), where I is an identity matrix of order 2
(C) BA is defined
(D) AB and BA both are defined and \(A B=B A\)
Choose the text correct answer from the options given below :

Read the following paragraph and answer the given questions.
Cancer detection is based on biopsy and histopathological studies. Techniques like radiography (use of X-rays), CT (computed tomography) and MRI (magnetic resonance imaging) are very useful to detect cancers of the internal organs. Do you know why mother's milk is considered very essential for the new-born infant? The yellowish fluid colostrum secreted by mother during the initial days of lactation has abundant antibodies (IgA) to protect the infant. Different species of Plasmodium (P. vivax, P. malaria and P. falciparum) are responsible for different types of malaria. Of these, malignant malaria caused by Plasmodium falciparum is the most serious one and can even be fatal. The exaggerated response of the immune system to certain antigens present in the environment is called allergy. The use of drugs like anti-histamine, adrenalin and steroids quickly reduce the symptoms of allergy. Drugs like barbiturates, amphetamines, benzodiazepines, and other similar drugs, that are normally used as medicines to help patients cope with mental illnesses like depression and insomnia, are often abused. Morphine is a very effective sedative and painkiller, and is very useful in patients who have undergone surgery.
The drug, which is very effective sedative and painkiller and useful for patients who have undergone surgery is -

As astronomical telescope of ten fold angular magnification has a length of 44 cm. The focal length of the objective is:

The half life of a first order reaction having rate constant, \(k=1.7 \times 10^{-5} s^{-1}\) is