List of practice Questions

If the kinetic energy of the particle is increased to 16 times its previous value, the percentage change in the de-Broglie wavelength of the particle is :

If the focal length of objective lens is increased then magnifying power of:

The angle of a prism is 'A'. One of its refracting surfaces is silvered. Light rays falling at an angle of incidence 2A on the first surface returns back through the same path after suffering reflection at the silvered surface. The refractive indexµ, of the prism is

Dependence of intensity of gravitational field (E) of earth with distance (r) from centre of earth is correctly represented by

A thin semicircular conducting ring (PQR) of radius 'r' is falling with its plane vertical in a horizontal magnetic field B, as shown in figure. The potential difference developed across the ring when its speed is v, is:

In an ammeter 0.2% of main current passes through the galvanometer. If resistance of galvanometer is G, the resistance of ammeter will be:

For the reaction:
\(X_2O4(l) → 2XO_2(g)\)
△U = 2.1 k cal, △S = 20 cal K^–l at 300 K.
Hence △G is

In the following reaction, the product (A) is :

Using the Gibbs energy change, \(△G° = + 63.3\  kJ\), for the following reaction,
\(Ag_2CO_3 (g) ⇋ 2Ag+ (aq) + CO_3^{2–} (aq)\)
the \(K_{sp}\) of \(Ag_2CO_3 \)(s) in water at \(25°C\) is :
\((R = 8.314\ J K^{–1} mol^{–1})\)

Identify \(Z\) in the sequence of reactions:
\(CH_3CH_2CH=CH_2  \xrightarrow{HBr/H_2O_2}Y \xrightarrow{C_2H_5ONa}Z\)

A gardener is digging a plot of land. As he gets tired, he works more slowly. After $' t '$ minutes he is digging at a rate of $\frac {2} {\sqrt {t}} $square metres per minute. How long will it take him to dig an area of $40$ square metres ?

Two concentric hollow spherical shells have radii $ r $ and $ R \left(R\,>>\,r\right) $ . A charge $ Q $ is distributed on them such that the surface charge densities are equal. The electric potential at the centre is

A steady current flows in a long wire. It is bent into a circular loop of one turn and the magnetic field at the centre of the coil is $ B $ . If the same wire is bent into a circular loop of $ n $ turns, the magnetic field at the centre of the coil is

A balloon with mass m is descending down with an acceleration a (where a < g). How much mass should be removed from it so that it starts moving up with an acceleration $a$?

Which property of colloids is not dependent on the charge on colloidal particles?

Which of the following will be most stable diazonium salt $(R\, N^{+}_{2}\,X^{-})$ ?

Which of the following will not be soluble in sodium hydrogen carbonate?

If $x+y\leq2,x \geq 0,y \geq 0$ the point at which maximum value of $3x + 2y$ attained will be

If the function $f(x)$ defined by $\frac {x^{100}}{100}+\frac {x^{99}}{100}+\dots \frac {x^2}{100}+x+1$ then $f'(0)$ is equal to

The general solution of the differential equation $\frac {dy}{dx}+\frac {y}{x}=3x$ is

Given $0 \leq x \leq \frac {1}{2}$ then the value of $\tan \left[\sin^{-1}\left\{\frac{x}{\sqrt {2}}+\frac {\sqrt {1-x^2}} {\sqrt {2}}\right\}-\sin^{-1}x\right]$ is

A stone of mass $0.05 \,kg$ is thrown vertically upwards. What is the direction and magnitude of net force on the stone during its upward motion ?

When longitudinal wave propagates, what happens in the region of compressions and rarefactions?

Energy of one mole of photons of radiation whose frequency is $ 5\times 10^{14}\,Hz $ is

A crystalline solid $X$ reacts with $dil. HCl$ to liberate a gas $Y.Y$ decolourises acidified $KMnO_4$. When a gas $'Z'$ is slowly passed into an aqueous solution of $Y$, colloidal sulphur is obtained. $X$ and $Z$ could be, respectively