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

Anonymous User Physics 13 Dec, 2018 87 views

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

Anonymous User Physics 13 Dec, 2018 1647 views

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

Anonymous User Physics 13 Dec, 2018 677 views

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.

Anonymous User Physics 12 Dec, 2018 313 views

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?

Amit tyagi Physics 09 Dec, 2018 1236 views

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

Anonymous User Biology 09 Dec, 2018 72 views

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

Anonymous User Physics 04 Dec, 2018 215 views

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?

Ashish Yadav Maths 01 Dec, 2018 77 views

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

Amit tyagi Chemistry 28 Nov, 2018 432 views

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?

Preeti Rai Maths 26 Nov, 2018 274 views

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

Anonymous User Maths 23 Nov, 2018 236 views

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?

Anonymous User Maths 23 Nov, 2018 865 views

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

Anonymous User Maths 18 Nov, 2018 158 views

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?

Anonymous User Physics 14 Nov, 2018 178 views

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

Anonymous User Physics 14 Nov, 2018 129 views

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?

Anonymous User Physics 12 Nov, 2018 2399 views

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?

Anonymous User Chemistry 12 Nov, 2018 381 views

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

Anshul Kumar Singh Maths 09 Nov, 2018 98 views

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

Ashish Yadav Physics 06 Nov, 2018 4027 views

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

Anonymous User Physics 30 Oct, 2018 523 views

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

Anonymous User Chemistry 22 Oct, 2018 1532 views

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

Mitali Rajpoot Physics 20 Oct, 2018 183 views

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?

Mitali Rajpoot Physics 20 Oct, 2018 373 views

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

Arun Sharma Chemistry 19 Oct, 2018 74 views

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?

Arun Sharma Chemistry 19 Oct, 2018 110 views

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

Preeti Rai Physics 19 Oct, 2018 84 views

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?

Preeti Rai Physics 19 Oct, 2018 74 views

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?

Anonymous User Physics IIT 16 Oct, 2018 174 views

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?

Devendra Yadav Physics 08 Oct, 2018 96 views

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

Anonymous User Maths 05 Oct, 2018 223 views

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?

Anonymous User Physics 03 Oct, 2018 166 views

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?

Anonymous User Maths 27 Sep, 2018 209 views

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?

Anonymous User Physics IIT 26 Sep, 2018 160 views

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?

Aryan Singh Maths IIT 24 Sep, 2018 238 views

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

Anonymous User Maths IIT 23 Sep, 2018 114 views

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?

Anonymous User Maths IIT 21 Sep, 2018 91 views

What is the Methods of Preparation of Alcohols?

Anonymous User Chemistry IIT 21 Sep, 2018 93 views

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 :

1. Nuclear charge and electron affinity
2. Ionization energy and electron affinity
3. Atomic radius and electron affinity
4. None of above.

Anonymous User Chemistry IIT 20 Sep, 2018 136 views

The helical structure of proteins is stabilized by?

Anonymous User Chemistry IIT 19 Sep, 2018 110 views

what is Moissan boron ?

Anonymous User Chemistry IIT 17 Sep, 2018 305 views

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

Anonymous User Chemistry IIT 17 Sep, 2018 611 views

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?

Anonymous User Maths Physics 17 Sep, 2018 94 views

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

Anonymous User Maths IIT 17 Sep, 2018 622 views

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?

Anonymous User Physics IIT 15 Sep, 2018 783 views

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 ?

Anonymous User Physics IIT 14 Sep, 2018 2028 views

What is Simple Harmonic Motion? Explain?

Anonymous User Physics IIT 13 Sep, 2018 77 views

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?

Anonymous User Maths IIT 13 Sep, 2018 1841 views

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?

Anonymous User Physics IIT 13 Sep, 2018 76 views