List of practice Questions

For which of the following voltages will the wavelengh of emitted $X$-rays will be minimum?

A wave is expressed by the equation $ y= a\,sin [\frac{\pi x}{2a} - \frac{\pi t}{2}]$ where $x$ and $y$ are in $m$ and $t$ in $s$. The distance travelled by the wave in $3 \,s$ is

According to Bohr's model, relation between the radius of an orbit and principal quantum number is

A cylindrical tube, open at both ends, has a fundamental frequency $f$ in air. The tube is dipped vertically in water so that half of it is in water. The fundamental frequency of the air column is

The work done in shifting a particle of mass $m$ from the centre of the earth to the surface of the earth is (Where $M$ is the mass of the earth and $R$ is the radius of the earth)

A thermally insulated vessel containing a gas whose molar mass is $M$ and ratio of specific heat $\gamma$ moves with velocity $v$. What is the change in temperature of the gas if the vessel is suddenly stopped?

A car is fitted with a convex side-view mirror of focal length $20 \,cm$. A second car $2.5\, m$ behind the first car is overtaking the first car at a relative speed of $15 \,m / s$. The speed of the image of the second car as seen in the mirror of the first one is

A body of mass $0.5\, kg$ is projected under gravity with a speed of $98\, m / s$ at an angle of $60^{\circ}$ with the horizontal. The change in momentum (in magnitude) of the body is

Chiasmata are most appropriately observed in meiosis during

In a Young's double slit experiment, the two slits act as coherent sources of waves of equal amplitude A and wavelength $\lambda$. In another experiment with the same arrangement the two slits are made to act as incoherent sources of waves of same amplitude and wavelength. If the intensity at the middle point of the screen in the first case is $I_1$ and in the second case is $I_2$, then the ratio $\frac{I_{1}}{I_{2}} $ is :

A beaker contains water up to a height $h_1$ and kerosene of height $h_2$ above water so that the total height of (water + kerosene) is $(h_1 + h_2)$. Refractive index of water is $\mu_{1}$ and that of kerosene is $\mu_{2}$. The apparent shift in the position of the bottom of the beaker when viewed from above is :

The value of enthalpy change ($\Delta$H) for the reaction $C_{2}H_{5}OH_{\left(I\right)} + 3O_{2\left(g\right)} \to 2CO_{2\left(g\right)} + 3H_{2}O_{\left(I\right)}$ at $27^{\circ}C$ is $-1366.5 \,kJ \,mol^{-1}.$ The value of internal energy change for the above reaction at this temperature will be :

The correct order of electron gain enthalpy with negative sign of F, Cl, Br and I, having atomic number 9, 17, 35 and 53 respectively, is:

The molecular velocity of any gas is:

When r, P and M represent rate of diffusion, pressure and molecular mass, respectively, then the ratio of the rates of diffusion $(r_A/r_B)$ of two gases A and B, is given as:

A 5.2 molal aqueous solution of methyl alcohol, $CH _{3} OH$ is supplied. What is the mole fraction of methyl alcohol in the solution?

Consider thiol anion $(RS^?)$ and alkoxy anion $(RO^?)$. Which of the following statements is correct ?

An ideal coil of $10\, H$ is joined in series with a resistance of $5 \,\Omega$ and battery of $5\, V,\, 2 s$ after joining the current flowing (in ampere) in the circuit will be

A rocket is fired upward from the earth surface such that it creates an acceleration of $19.6\, m / s ^{2}$. If after $5\, s$, its engine is switched off, the maximum height of the rocket from earth's surface would be

A $60\, kg$ weight is dragged on a horizontal surface by a rope through a distance of $2m$. If coefficient of friction is $ \mu =0.5, $ the angle of rope with surface is $60^{\circ}$ and $g=9.8\,m/{s}^{2}, $ then work done is

A 0.2 kg object at rest is subjected to a force $\left(0.3\hat{i}-0.4\hat{ j}\right)$ N. What is the velocity after 6 s?

As shown in the figure a magnet is moved with a fast speed towards a coil at rest. Due to this induced emf, induced current and induced charge in the coil is $E,\, I$ and $Q$ respectively. If the speed of the magnet is doubled, the incorrect statement is

Two tangent galvanometer having coils of the same radius are connected in series. A current flowing in them produces deflection of $60^{\circ}$ and $45^{\circ}$ respectively. The ratio of the number of turns in the coils is

Two longitudinal waves given by equations : $y_1 (x, t) = 2a$ sin ($\omega t - kx$) and $y_2 (x, t)$ = a sin ($2\omega t - 2kx$) will have equal intensity. Intensity of waves of given frequency in same medium is proportional to square of amplitude only.

The transverse displacement $y(x, t)$ of a wave on a string is given by $y(x, t)=e^{-\left(a x^{2}+b t^{2}+2 \sqrt{a b} x t\right)}$ This represents a :