The height of transmitting antenna and receiving antenna are 45 m and 80 m. If the radius of earth is \( 6.4 \times 10^6 \text{ m} \), then the maximum distance between the two antennas for satisfactory communication in LOS mode is:

Identify the correct statements
(A) Electric current arises due to the continuous flow of electrons or ions.
(B) A current flows through a conductor only when there is an electric field within the
conductor.
(C) The drift velocity of electrons is directly proportional to the applied electric field.
(D) The average thermal velocity of the electrons in a conductor is zero.
(E) In the absence of an electric field, the electrons in a conductor are at rest.
Choose the correct answer from the options given below :

Two particles x and y having equal charge, after being accelerated through the same potential difference, enter a region of a uniform magnetic field. They describe circular paths of radii \( R_1 \) and \( R_2 \), respectively. The ratio of the mass of x to that of y is:

A short bar magnet placed with its axis at \(30^\circ\) with a uniform external magnetic field of 0.16 T experiences a torque of magnitude 0.48 J. The magnetic moment of the bar magnet will be

The current in a circuit having constant resistance is tripled. The power dissipation will become :

What physical quantity is the same for X-rays of wavelength \( 10^{-10} \) m, red light of wavelength 680 nm and radiowaves of wavelength 50 m?

Match List-I with List-II for convex lens (symbols have their usual meanings)

List-I (Position of Object)	List-II (Details of image)
(A) at 2F	(l) \(m>1\), virtual
(B) at F	(II) \(m <1\), real
(C) between lens and F	(III) m = 1 , real
(D) between \(\infty\) and 2F	(IV) \(m \gg 1\), real

Choose the correct answer from the options given below :

Match List-l with List-ll

List-l (Disease)	List-II (Characteristic symptoms)
(A) Malaria	(I) Inflammation of lower limb
(B) Filariasis	(II) Cycles of fever
(C) Ringworms	(III) Blood clots and excess mucus in stools
(D) Amoebiasis	(IV) Scaly lesions on nails

Choose the correct answer from the options given below:

The value of integral \(\int \frac{\cos 2 x-\cos 2 \alpha}{\cos x-\cos \alpha} d x\), where \(\alpha\) is a constant is :

Read the following passage carefully and answer the given questions.
Plasmodium, a tiny protozoan is responsible for the disease malaria. 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. Innate immunity consist of four types of barriers. These are – (i) Physical barriers- skin on our body is the main barrier which prevents entry of the micro-organisms. (ii) Physiological barriers- Acid in the stomach, saliva in the mouth, tears from eyes-all prevent microbial growth. (iii) Cellular barriers- Certain types of leukocytes (WBC) of our body like polymorpho-nuclear leukocytes (PMNL-neutrophils) and monocytes and natural killer (type of lymphocytes) in the blood as well as macrophages in tissues can phagocytose and destroy microbes. (iv) Cytokine barriers- virus-infected cells secrete proteins called interferons which protect non-infected cells from further viral infection. Allergy is due to the release of chemicals like histamine and serotonin from the mast cells. 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.
Malignant malaria is caused by _____ is the most serious one and can even be fatal.

In India, the number of biosphere reserves and national parks are -

Match List I with List II

LIST I	LIST II
A. Curd	I. Streptococcus
B. Butyric acid	II. Propionibacterium sharmanii
C. Swiss cheese	III. Clostridium butylicum
D. Clot buster	IV. Lactobacillus

Choose the correct answer from the options given below:

What is the name of the reaction when acetamide is converted to methylamine?