List of practice Questions

The mean and variance of the marks obtained by the students in a test are 10 and 4 respectively Later, the marks of one of the students is increased from 8 to 12 If the new mean of the marks is $10.2$, then their new variance is equal to :

The number of integral values of \(k\), for which one root of the equation \[2x^2 - 8x + k = 0\] lies in the interval \((1, 2)\) and its other root lies in the interval \((2, 3)\), is:

How many bromo products are formed when ethane is reacted with excess of Br2 on heating?

The mean and standard deviation of 10 observations are 20 and 8 respectively. Later on, it was observed that one observation was recorded as 50 instead of 40. Then the correct variance is:

The heat passing through the cross-section of a conductor, varies with time ‘t’ as \(Q(t) = αt – βt^2 + γt^3\). (\(α, β\) and \(γ\) are positive constants.) The minimum heat current through the conductor is
A guitar string of length 90 cm vibrates with a fundamental frequency of 120 Hz. The length of the string producing a fundamental frequency of 180 Hz will be _______ cm.
Match List l with List ll.
List I Coordination Complex List II Number of unpaired electrons
(I) [Cr(CN)6]3- (a) 0
(II) [Fe(H2O)6]2+ (b) 3
(III) [Co(NH3)6]3+ (c) 2
(IV) [Ni(NH3)6]2+ (d) 4
Choose the correct answer from the options given below:
The variation of kinetic energy (KE) of a particle executing simple harmonic motion with the displacement (x) starting from mean position to extreme position (A) is given by:
Which of the following statements is correct about freons?

Separation between earth and sun is given by 1.5 × 106 km. Time period of another planet is 2.83 year. Find distance of another planet from sun?

Match List I with List II 

List IList II
AIFittig reaction
BIIWurtz Fittig reaction
CIIIFinkelstein reaction
D\(C_{2}H_{5}CI + NaI \rightarrow C_{2}H_{5}I + NaCl\)IVSandmeyer reaction

 Choose the correct answer from the options given below:

Statement I: When a Si sample is doped with Boron, it becomes P type and when doped by Arsenic it becomes N-type semi conductor such that P-type has excess holes and N-type has excess electrons.
Statement II: When such P-type and N-type semi-conductors, are fused to make a junction, a current will automatically flow which can be detected with an externally connected ammeter.
In the light of above statements, choose the most appropriate answer from the options given below
If $\int \limits_0^\pi \frac{5^{\cos x}\left(1+\cos x \cos 3 x+\cos ^2 x+\cos ^3 x \cos 3 x\right) d x}{1+5^{\cos x}}=\frac{ k \pi}{16}$, then $k$ is equal to
Glycosidic linkage between $C _1$ of $\alpha$-glucose and $C_2$ of $\beta$-fructose is found in
The resistance of a wire is $5 \Omega$. It's new resistance in ohm if stretched to 5 times of it's original length will be:

How many moles of Ba3(PO4)2 will be formed by the reaction of 5 moles of BaCl2 and 3 moles of Na3(PO4).

The number of ways to distribute 20 chocolates among three students such that each student gets atleast one chocolate is
Two identical particles each of mass m, move in circular path due to their own mutual gravitational force. Find the velocity of the particle if the radius of the circular path is a.
The energy band gap of semiconducting material to produce violet (wavelength = $4000 \mathring{A}$ ) LED is ______$eV$ (Round off to the nearest integer)
Identify the correct statements from the following:
A. Work done by a man in lifting a bucket out of a well by means of a rope tied to the bucket is negative.
B. Work done by gravitational force in lifting a bucket out of a well by a rope tied to the bucket is negative.  
C. Work done by friction on a body sliding down an inclined plane is positive.  
D. Work done by an applied force on a body moving on a rough horizontal plane with uniform velocity in zero.  
E. Work done by the air resistance on an oscillating pendulum in negative.  
Choose the correct answer from the options given below:
A particle of mass 10 g moves in a straight line with retardation 2x, where x is the displacement in SI units. Its loss of kinetic energy for above displacement is \((10/x)^{-n}\)J. The value of n will be ____________
If the maximum load carried by an elevator is 1400 kg (600 kg - Passengers + 800 kg- elevator), which is moving up with a uniform speed of 3 ms-1 and the frictional force acting on it is 2000 N, then the maximum power used by the motor is ____ kW. (g=10 m/s2)
Let A = {1, 2, 3, 4, 5} and B = {1, 2, 3, 4, 5, 6). Then the number of functions f: A→B satisfying f(1) + f(2) = f(4)-1 is equal to _________ .
Which of the following compounds is an example of Freon?
The number of correct statements from the following is ______
A. Ecell is an intensive parameter
B. A negative Eθ means that the redox couple is a stronger reducing agent than the H– H2 couple.
C. The amount of electricity required for oxidation or reduction depends on the stoichiometry of the electrode reaction.
D. The amount of chemical reaction which occurs at any electrode during electrolysis by a current is proportional to the quantity of electricity passed through the electrolyte.