Moissan boron is

An ‘fcc’ in a unit cell of aluminium contains the equivalent of how many atoms ?

A fire of lithium, sodium and potassium can be extinguished by

Which of the following pairs show reverse properties on moving along a period from left to right and from up to down in a group :

Which is not true for beryllium ?

The temperature of an ideal gas is reduced from 927°C to 27°C. the r.m.s. velocity of the molecules becomes.

Given the molecular formula of the hexa-coordinated complexes (i) CoCl3.6NH3, (ii) CoCl3.5NH3, (iii) CoCl3.4NH3 If the number of co-ordinated NH3 molecules in (i), (ii) and (iii) respectively are 6, 5, 4, the primary valencies in (i), (ii) and (iii) are :

A white sodium salt dissolves readily in water to give a solution which is neutral to litmus. When silver nitrate solution is added to the solution, a white precipitate is obtained which does not dissolve in dil. HNO3. The anion could be

Exactly 2 machines out of 4 are faulty. They are tested one by one in a random order till both the faulty machines are identified. Then, the probability that only two tests are required is :

Two dice are thrown together. Then the probability, that the sum of numbers appearing on them is a prime number, is

A school has four sections of chemistry in class XII having 40, 35, 45 and 42 students. The mean marks obtained in Chemistry test are 50, 60, 55 and 45 respectively for the four sections, the over all average of marks per students is

If the latusrectum of an ellipse with axis along X-axis and centre at origin is 10 and distance between foci is length of minor axis, then the equation of the ellipse is

The coefficient of x4 in the expansion of

Locus of the points which are at equal distance from 3x + 4y – 11 = 0 and 12x + 5y + 2 = 0 and which is near the origin is

The sum of the series 3.6 + 4.7 + 5.8 + ......upto (n – 2) terms is?

The value of

if 3f(x) - f(1 / x) = , then

The function f(x) = log (1 +x / 1 -x) stisfies the equation

Ethyl isocyanide on hydrolysis in acidic medium generates

When primary amine reacts with chloroform in 5. ethanolic KOH then the product is

The compound formed on heating chlorobenzene with chloral in the presence of concentrated sulphuric acid is

The smog is essentially caused by the presence of

Which one of the following types of drugs reduces fever?

Let R={(1,3),(4,2),(2,4),(2,3),(3,1)}be a relation on the set A = {1, 2, 3, 4}. The relation R is

Two lenses of power –15 D and +5 D are in contact with each other. What will be the focal length of the combination?

The two functional groups present in a typical 29. 30. carbohydrate are?

Copper crystallizes in fcc with a unit cell length of 361 pm. What is the radius of copper atom ?

Two liquids X and Y form an ideal solution. At 300 K, vapour pressure of the solution containing 1mol of X and 3 mol of Y is 550 mm Hg.Atthesame temperature, if 1 mol of Y is further added to this solution, vapour pressure of the solution increases by 10 mm Hg. Vapour pressure (in mm Hg) of X and Y in their pure states will be, respectively

Can Apples float in water ?

What is The highest recorded body temperature at which a human can survived ?

Which is strongest muscle in human body

Explain HIV/AIDS.

Does Plants are capable of recognizing their siblings?

Does Oysters change their sex?

Which is most poisonous vertebrate in world?

How much time Common cold virus can survive outside the body?

Can a person live with one lung ?

Can Our lungs are float on water?

What is alveoli?

What is neuroplasticity?

Why do we talk in our steep? Why we see unknown faces in the dream?

What are paracetamol and steroidal drugs and how do they work?

A light ray is incident perpendicular to one face of a 90° prism and is totally internally reflected at the glass air interface. If the angle of reflection is 45°, we conclude that the refractive index *n*

To get three images of a single object, one should have two plane mirrors at an angle of

The image formed by an objective of a compound microscope is

An astronomical telescope has a large aperture to

Which of the following is used in optical fibres?

Wavelength of light used in an optical instrument are = 4000 Å and = 5000 Å, then ratio of their respective resolving powers (corresponding to and ) is

If two mirrors are kept at 60° to each other, then the number of images formed by them is