A marble block of mass $$2$$ $$kg$$ lying on ice when given a velocity of $$6$$ $$m/s$$ is stopped by friction in $$10$$ $$s.$$ Then the coefficient of friction is

A block of mass $$M$$ is pulled along a horizontal frictionless surface by a rope of mass $$m.$$ If a force $$P$$ is applied at the free end of the rope, the force exerted by the rope on the block is

When the current changes from $$+2A$$ to $$-2A$$ in $$0.05$$ second, an $$e.m.f.$$ of $$8$$ $$V$$ is inducted in a coil. The coefficient of self- induction of the coil is

Two coils are placed close to each other. The mutual inductance of the pair of coils depends upon

A particle performing uniform circular motion has angular frequency is doubled & its kinetic energy halved, then the new angular momentum is

Let $$\overrightarrow{F}$$ be the force acting on a particle having position vector $$\overrightarrow{r},$$ and $$\overrightarrow{\tau }$$ be the torque of this force about the origin. Then

A circular disc $$X$$ of radius $$R$$ is made from an iron plate of thickness $$t,$$ and another disc $$Y$$ of radius $$4$$ $$R$$ is made from an iron plate of thickness {t \over 4}. Then the relation between the moment of inertia $$I_X$$ and $$I_Y$$ is

According to the kinetic theory of gases, in an ideal gas, between two successive collisions of a gas molecule travels

Butene-1 may be converted to butane by reaction with

On mixing a certain alkane with chlorine and irradiating it with ultravioletlight, it forms only one monochloroalkane. This alkane could be

Ammonia forms the complex ion [Cu(NH3)4]2+ with copper ions in alkaline solutions but not in acidic solutions. What is the reason for it?

One mole of the complex compound Co(NH3)5Cl3, gives 3 moles of ions on dissolution in water. One mole of the same complex reacts with two moles of AgNO3 solution to yield two moles of AgCl (s). The structure of the complex is :

In the coordination compound, K4[Ni(CN)4], the oxidation state of nickel is :

The solubility in water of a sparingly soluble salt AB2 is 1.0 $$\times$$ 10-5 mol L-1. Its solubility product number will be :

Which one of the following statements is not true?

When rain is accompanied by a thunderstorm, the collected rain water will have a pH value :

Which one of the following groupings represents a collection of isoelectronic species? (At. nos. : Cs : 55, Br : 35)

In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inter-orbit jumps of the electron for Bohr orbits in an atom of hydrogen

The de Broglie wavelength of a tennis ball of mass 60 g moving with a velocity of 10 meters per second is approximately

The orbital angular momentum for an electron revolving in an orbit is given by \sqrt {l(l + 1)} {h \over {2\pi }}. This momentum for an s-electron will be given by