The colour of the X2 molecules of group 17 elements changes gradually from yellow to violet down the

group. This is due to

[A] the physical state of X2 at atom temperature changes from gas to solid down the group

[B] decrease in HOMO-LUMO gap down the group

[C] decrease in gap down the group

[D] decrease in ionization energy down the group

Name 3 isostructural molecules

Thiol group is present in :

(1) Cystine

(2) Cysteine

(3) Methionine

(4) Cytosine

What is **isoelectronic species**?

Please explain?

The formation of which of the following polymers involves hydrolysis reaction?

(1) Bakelite

(2) Nylon 6, 6

(3) Terylene

(4) Nylon 6

A man grows into a giant such that his linear dimensions increase by a factor of 9. Assuming that his

density remains same, the stress in the leg will change by a factor of?

In a common emitter amplifier circuit using an n-p-n transistor, the phase difference between the input and

the output voltages will be?

The electric field inside the cavity of radius a at a distance r from the centre of cavity is?

What is meant by electrical resistivity of a material? Derive its S.I. unit. Describe an experiment to study the factor on which the resistance of a conducting wire depends.

what is Ph value of water.?

The number of types of bonds between two carbon atoms in calcium carbide is?

then value of cos 4x?

The carbon–based reduction method is NOT used for the extraction of:

**a. **tin from

**b.** iron from

**c.** aluminium from

**d.** magnesium from

Explain faraday’s ist Law of electrolysis

Explain faraday’s 2nd Law of electrolysis

What is paramagnetic and which of the following species is not paramagnetic?

a.CO

b.

c.

d. NO

How SMOG is formed?

What is source of SMOG?

What is SMOG?

Why water and oil does not mix together?

In the nuclear transmutation

find the value of (X,Y)

The sum of the number of lone pairs of electrons on each central atom in the following species is

(Atomic numbers : N 7,F 9,S 16,Br 35,Te 52,Xe 54)

The number of diamagnetic species is

(Atomic numbers: H = 1, He = 2, Li = 3, Be = 4, B = 5, C = 6, N = 7, O = 8, F = 9)

How many un-paired electron are there in

what is newton's first law

Calculate the molarity of a nitric acid solution. The density of the solution is 1.42 g/cm3 and the solution is 70 % HNO3 by mass.

A solution is prepared by adding 100 mL of water to 50.0 mL of 0.6 M CaCl2 . Determine the concentration of chloride ions in the final solution.

(A) In the region 0 < r < R, the magnetic field is non-zero (B) In the region R < r < 2R, the magnetic field is along the common axis. (C) In the region R < r < 2R, the magnetic field is tangential to the circle of radius r, centered on the axis. (D) In the region r > 2R, the magnetic field is non-zero.

In a triangle PQR, P is the largest angle and cos P = 1/3. Further the incircle of the triangle touches the sides PQ, QR and RP at N, L and M respectively, such that the lengths of PN, QL and RM are consecutive even integers. Then possible length(s) of the side(s) of the triangle is (are) ?

Sound travels with a different speed in media. In what order does the velocity of sound increase in these media?

What is the role of HCl in our Stomach?

Words of length 10 are formed using the letters, A, B, C, D, E, F, G, H, I, J. Let x be the number of such words where no letter is repeated ; and let y be the number of such words where exactly one letter is repeated twice and no other letter is repeated. Then, y/9x=?

A stationary source emits sound of frequency f0 = 492 Hz. The sound is reflected by a large car approaching the source with a speed of 2 m/s . The reflected signal is received by the soruce and superposed with the original. What will be the beat frequency of the resulting signal in Hz? (Given that the speed of sound in air is 330 m/s and the car reflects the sound at the frequency it has received).

Enzymes and name of any enzyme of our digestive system and its function.

Of the following natural phenomena, tell which one known in Sanskrit as 'deer's thirst'? A. Rainbow B. Earthshine C. Halo D. Mirag

Why It takes much longer to cook food in the hills than in the plains?

Why Stars twinkle?

Suitable impurities are added to a semiconductor depending on its use. This is done in order to

On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because

Sound of frequency below 20 Hz is called ?

Why RADAR is used ?

Materials for rain-proof coats and tents owe their water-proof properties to A. surface tension B. viscosity C. specific gravity D. elasticity

Point A is at a lower electrical potential than point B. An electron between them on the line joining them will A. move towards A B. move towards B C. move at right angles to the line joining A and B D. remain at rest

Why On a rainy day, small oil films on water show brilliant colors. This is due to

Lux is the SI unit of A. intensity of illumination B. luminous efficiency C. luminous flux D. luminous intensity Lux is the SI unit of A. intensity of illumination B. luminous efficiency C. luminous flux D. luminous intensity

Find the maximum velocity for the overturn of a car moving on a circular track of radius 100 m. The co-efficient of friction between the road and tyre is 0.2

Why It is more difficult to walk on a sandy road than on a concrete road ?

how much amount of Magnetism at the centre of a bar magnet ?

Why Rectifiers are used ?