Write two important limitations of Rutherford nuclear model of the atom.

What percentage of a given mass of a radioactive substance will be left un decayed after four half lives?

A glass lens of refractive index 1.45 disappears when immersed in a liquid. What is the value of refractive index of the liquid?

A charge is distributed uniformly over a ring of radius a.Obtain an expression for electric intensity E at a point on the axis of the ring.Hence show that for the points at large distance from the ring, it behave like a point charge.

The optical path of monochromatic light is same as if it goes from 4.0 cm of glass or 4.5 cm of water.If the reflective index of glass is 1.53 then what should be reflective index water?

Lady bird (Beetle with red and black marking) is used as biological control of ?

The kinetic energy needed to project a body of mass m from the earth surface (radius R) to infinity is?

5 letters are to be posted in 5 post boxes. If any number of letters can be posted in 5 post boxes, what is the probability that each box contains only one letter?

Two fast moving particles X and Y are associated with deBroglie wavelengths 1 nm and 4 nm respectively. If mass ofX is nine times the mass of Y, the ratio of kinetic energies ofX and Y would be

A stone is dropped into a quiet lake and waves move in a circle at a speed of 3.5 cm/sec. At the instant when the radius of the circular wave is 7.5 cm. How fast is the enclosed area increasing?

A dice is tossed 5 times. Getting an odd number is considere a success. Then the variance of distribution of success is?

A drunken man takes a step forward with probability 0.4 and backwards with probability 0.6. Find the probability that at the end of eleven steps, he is on e step away from the star ting point?

Let S be a finite set containing n elements. Then the total number of binary operations on S is:

A tuning fork arrangement (pair) produces 4 beats/sec with one fork of frequency 288 cps. A little wax is placed on the unknown fork and it then produces 2 beats/sec. The frequency of the unknown fork is?

A parallel plate condenser with a dielectric of dielectric constant K between the plates has a capacity C and is charged to a potential V volt. The dielectric slab is slowly removed from between the plates and then reinserted. The net work done by the system in this process is

An electrical cable of copper has just one wire of radius 9mm. Its resistance is 5 ohm. This single copper wire of the cable is replaced by 6 different well insulated copper wires each of radius 3 mm. The total resistance of the cable will now be equal to?

Though the five d-orbitals are degenerate, the first four d-orbitals are similar to each other in shape whereas the fifth d-orbital is different from others. What is the designation of the fifth orbital?

Total number of possible matrices of order 3 × 3 with each entry 2 or 0 is?

A thin glass (refractive index 1.5) lens has optical power of –5 D in air. Its optical power in a liquid medium with refractive index 1.6 will be

In Young's double slit experiment, one of the slit is wider than other, so that amplitude of the light from one slit is double of that from other slit. If be the maximum intensity, the resultant intensity I when they interfere at phase difference f is given by

How many P–H and O–H bonds respectively, are present in molecule?

How would you expect the damage done to a brick wall to differ in the event of separate collisions with the elephant and cannonball?

Being in the wrong place when an African elephant—mass = 6000 kg, velocity = 10 m/s—is charging can really ruin your day. How fast would a 1 kg cannon ball travel if it had the same kinetic energy as the elephant?

How many molecules of O2 are present in 1.00L of O2 at STP?

What volume of O2 measured at 1.86 ×× 106Pa and 375k, is required to react entirely with 1.78l of H2, measured at the same temperature and pressure, to give H2O?

Kepler’s second law states that the radius vector to a planet from the sun sweeps out equal areas in equal intervals of time.

This law is a consequence of the conservation of: (a) Time (b) Mass (c) Angular momentum (d) Linear momentum

A planet moves around the sun in an elliptical orbit with the sun at one of its foci. What is the physical quantity associated with the motion of the planet that remains constant with time?

A block of mass 0.50 kg is moving with a speed of 2.00 ms–1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is?

Light of wavelength 200 Å fall on aluminium surface. Work function of aluminium is 4.2 eV. What is the kinetic energy of the fastest emitted photoelectrons?

Differentiate the following function w.r.t. x :

If three elements A, B, C crystallise in a cubic solid lattice with A atoms at the corners, B atoms at the cube centre, and C atoms at the center of the face of the cube,then write the formula of the compound?

A doctor is called to see a sick child. The doctor has prior information that 80% of sick children in that area have the flu, while the other 20% are sick with measles. Assume that there is no other disease in that area. A well-known symptom of measles is a rash. From the past records it is known that, chances of having rashes given that sick child is suffering from measles is 0.95. However, occasionally children with flu also develop rash, whose chances are 0.08. Upon examining the child, the doctor finds a rash. What is the probability that the child has measles?

At very high temperatures vibrational degrees also becomes active. At such temperatures an ideal diatomic gas has a molar specific heat at constant pressure, Cp is?

A triangular park is enclosed on two sides by a fence and on the third side by a straight river bank. The two sides having fence are of same length x .The maximum area enclosed by the park is?

Coefficient of variation of two distributions are 60 and 70, and their standard deviations are 21 and 16, respectively. Their arithmetic means are?

An arch is in the form of semi-ellipse. It is 8m wide and 2m high at the centre. Then, the height of the arch at a point1.5m from one end is?

What is the Methods of Preparation of Alcohols?

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 :

- Nuclear charge and electron affinity
- Ionization energy and electron affinity
- Atomic radius and electron affinity
- None of above.

The helical structure of proteins is stabilized by?

what is Moissan boron ?

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

An arch is in the form of semi-ellipse. It is 8m wide and 2m high at the centre. Then, the height of the arch at a point1.5m from one end is?

Coefficient of variation of two distributions are 60 and 70,and their standard deviations are 21 and 16, respectively.Their arithmetic means are?

the radius of curvature of a thin plano-convex lens is 10 cm(of curved surface) and the refractive index is 1.5. If the plane surface is silvered, then it behaves like a concave mirror of focal length?

A body initially at 80°C cools to 64°C in 5 minutes and to52°C in 10 minutes. The temperature of the body after 15minutes will be ?

What is Simple Harmonic Motion? Explain?

A school has four sections of chemistry in class XII having40, 35, 45 and 42 students. The mean marks obtained inChemistry test are 50, 60, 55 and 45 respectively for the four sections, the over all average of marks per students is?

t very high temperatures vibrational degrees also becomes active. At such temperatures an ideal diatomic gas has a molar specific heat at constant pressure, Cp is?