A glass rod, rubbed with silk gets positively charged, why ?

A battery has an e.m.f 12 V and internal resistance 2 \(\Omega\) This battery is connected to a variable resistor 0 to 5 \(\Omega\). The value of current for which the rate of heat production in the resistor is maximum:

A straight wire of mass 300 g and length 1.5 m carries a current of 2 A. It is suspended in mid air by a uniform horizontal magnetic field. The magnitude of the magnetic field is
(Neglect the earth's magnetic field and \( g = 10 \text{ m/s}^2 \))

What is the distance that a beam of light of wavelength 500 nm can travel without significant broadening, if the diffracting aperture is 3 mm wide ?

A rectangular loop ABCD made of uniform wire is a part of an electric circuit shown in the given figure. The length AD = BC = 5 mm. The sides AB and DC are long compared to the other two sides. What will be the magnetic force per unit length acting on the wire AB if the ammeter reading is 8 A?

The amplitude of the magnetic field of a harmonic electromagnetic wave in vacuum is \(B_0=610 nT\). The amplitude of the electric field of the wave is:

The circuits where transformers are used :

If the electric field is given by \(E = (8i + 4j + 3k) NC^{-1}\), the electric flux passing through a surface of area 100 \(m^2\) lying in x-y plane would be :

The necessary conditions for total internal reflection are
(A) Light must travel from denser to rarer medium.
(B) The angle of incidence in the denser medium must be less than the critical angle for the two media.
(C) Light must travel from rarer to denser medium.
(D) The angle of incidence in the denser medium must be greater than the critical angle for the two media.
Choose the correct answer from the options given below:

Read the following paragraph and answer the given questions:
DRUGS AND ALCOHOL ABUSE
The drugs, commonly abused are opioids, cannabinoids, and coca alkaloids. Opioids are the drugs, which bind to specific opioid receptors present in our central nervous system and gastrointestinal tract. Heroin, commonly called smack is chemically diacetylmorphine which is a white, odourless, bitter crystalline compound. Cannabinoids are a group of chemicals, which interact with cannabinoid receptors present principally in the brain. Natural cannabinoids are obtained from the inflorescences of the plant Cannabis sativa. The flower tops, leaves and the resin of cannabis plant are used in various combinations to produce marijuana, hashish, charas and ganja. Generally taken by inhalation and oral ingestion, these are known for their effects on cardiovascular system of the body. It interferes with the transport of the neuro-transmitter dopamine. Cocaine, commonly called coke or crack is usually snorted. It has a potent stimulating action on central nervous system, producing a sense of euphoria and increased energy. Excessive dosage of cocaine causes hallucinations. Other well-known plants with hallucinogenic properties are Atropa belladona and Datura. These days cannabinoids are also being abused by some sportspersons. 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. Several plants, fruits and seeds having hallucinogenic properties have been used for hundreds of years in folk-medicine, religious ceremonies and rituals all over the globe.
Which one of the following drugs is known for its effects on the cardiovascular system of the body?

match List - I with List - II

List - I	List - II
(A) \(\tan ^{-1}\left(\frac{2}{11}\right)+\tan ^{-1}\left(\frac{7}{24}\right)\)	(I) \(\frac{3 \pi}{4}\)
(B) \(\tan ^{-1} 2+\tan ^{-1} 3\)	(II) \(\pi\)
(C) \(\tan ^{-1} 1+\tan ^{-1} 2+\tan ^{-1} 3\)	(III) \(\tan ^{-1}\left(\frac{1}{2}\right)\)
(D) \(\tan ^{-1}\left(\frac{1}{7}\right)+\tan ^{-1}\left(\frac{1}{13}\right)\)	(IV) \(\tan ^{-1}\left(\frac{2}{9}\right)\)

Choose the correct answer from the options given below:

Which is not a type of sexually transmitted infections?

If for the following data :

YEAR (X)	2000	2001	2002	2003	2004	2005	2006
PRODUCTION (iN TONNES) (Y)	40	45	46	42	47	50	46

the equation of the straight line trend is \(y=45.143+1.036(x-2003)\), then the trend value for the year 2004 is