List of practice Questions

The standard deviation of n observations $x_1,x_2,\dots x_n$ is 2 If $\sum _{i=1}^n{x}_i=20$ and $\sum _{i=1}^n{x}_i^2=100,$ then $n$ is equal to

The sum of n terms of two AP's are in the ratio of $(3n+8):(7n+15)$. Find the ratio of their ${12}^{\text{th }}$ terms.

If a point P is equidistant from A(1, 3), B(-3, 5) and C(5, -1), then PA is equal to

The shortest distance from the point (1, 2, -1) to the surface of the sphere x² + y² + z² = 54 is

If $\sin \theta =\frac{2t}{1+t^2}$ and $\theta$ lies in the second quadrant, then $\cos \theta$ is equal to

Evaluate the integral: ${\int }_1^2\log xdx$

A coin is biased so that the head is 3 times as likely to occur as tail.If the coin is tossed twice,find the probability distribution of number of tails.

Consider the following species $(\mathrm{I}){\mathrm{S}}_4{\mathrm{O}}_6^{2-}$$(\mathrm{II}){\mathrm{S}}_3{\mathrm{O}}_9$$(\mathrm{III}){\mathrm{S}}_2{\mathrm{O}}_5^{2-}$$(\mathrm{IV}){\mathrm{P}}_3{\mathrm{O}}_9^{3-}$Which of the above species have same number of $X-0-X$ linkages? $(X=P\text{ or }S)$

Q in the above sequence of reactions is

The correct statement(s) about following sugars (X) and (Y) is/are:

Blackened oil painting can be restored into original form by the action of:

The addition of HBr to 2-pentene gives

Which one of the following observations is not true when a mixture of KCl, K2Cr2O7 and conc. H2SO4 is warmed carefully?

A spherical mirror and a thin spherical lens have each a focal length of −15 cm. The mirror and the lens are likely to be

Consider the following diagram and mark the correct answer.

Blood group agglutinogens $A$ and $B$ are found:

By which of the following defects, thalassemia is caused?

Digestion and absorption in the human body happens between ingestion and elimination. During digestion there are many enzymes which help to break down our food in the various organs of our digestive system. Which of the following enzymes is responsible for breaking down fats during digestion?

Doctors use stethoscope to hear the sounds produced during each cardiac cycle. The second sound is heard when :

ELISA is:

How many genotypes of sickle cell anaemia are possible in a population?

In which of the following places thalassemia is not common?

In which plants mechanical tissue is best developed?