List of practice Questions

Identify the electron rich hydrides from the following
If the energy gap of a semiconductor used for the fabrication of an LED is nearly 1.9 eV, then the color of the light emitted by the LED is
When the receiving antenna is on the ground, the range of a transmitting antenna of height 980 m is (Radius of the earth = 6400 km)
The energy associated with electron in first orbit of hydrogen atom is \(-2.18 \times 10^{-18}\) J. The frequency of the light required (in Hz) to excite the electron to fifth orbit is (\(h=6.6 \times 10^{-34}\) Js)
In Sr (Z=38), the number of electrons with \(l=0\) is x, number of electrons with \(l=2\) is y. \((x-y)\) is equal to (\(l\) = Azimuthal quantum number)
Match the following
The correct answer is
Observe the following data (\(\Delta_i H_1\), \(\Delta_i H_2\) and \(\Delta_{eg}H\) represent the first, second ionisation enthalpies and electron gain enthalpy respectively).
Using the data identify the most reactive metal.
The sum of bond order of \(O_2\), \(O_2^-\), \(O_2^{2-}\) and \(O_2^+\) is equal to
An electric bulb, an open coil inductor, an ac source and a key are all connected in series to form a closed circuit. The key is closed and after some time an iron rod is inserted into the interior of the inductor, then
If the rate of change in electric flux between the plates of a capacitor is \(9\pi \times 10^3 \text{ Vms}^{-1}\), then the displacement current inside the capacitor is
20 kV electrons can produce X-rays with a minimum wavelength of
The ratio of wavelengths of second line in Balmer series and the first line in Lyman series of hydrogen atom is
A radioactive material of half-life 2.5 hours emits radiation that is 32 times the safe maximum level. The time (in hours) after which the material can be handled safely is
If the number of uranium nuclei required per hour to produce a power of 64 kW is \(7.2 \times 10^{18}\), then the energy released per fission is
According to a graph drawn between the input and output voltages of a transistor connected in common emitter configuration, the region in which transistor acts as a switch is
The potential difference between points C and D of the electrical circuit shown in the figure is
The length of a potentiometer wire is 2.5 m and its resistance is 8 Ω. A cell of negligible internal resistance and emf of 2.5 V is connected in series with a resistance of 242 Ω in the primary circuit. The potential difference between two points separated by a distance of 20 cm on the potentiometer wire is
The magnetic field due to a current carrying circular coil on its axis at a distance of \(\sqrt{2} d\) from the centre of the coil is B. If d is the diameter of the coil, then the magnetic field at the centre of the coil is
A square coil of side 10 cm having 200 turns is placed in a uniform magnetic field of 2 T such that the plane of the coil is in the direction of magnetic field. If the current through the coil is 3 mA, then the torque acting on the coil is
The magnetic field at a point P on the axis of a short bar magnet of magnetic moment M is B. If another short bar magnet of magnetic moment 2M is placed on the first magnet such that their axes are perpendicular and their centres coincide. The resultant magnetic field at the point P due to both the magnets is
A circular coil of area \(3 \times 10^{-2} \text{ m}^2\), 900 turns and a resistance of 1.8 Ω is placed with its plane perpendicular to a uniform magnetic field of \(3.5 \times 10^{-5}\) T. The current induced in the coil when it is rotated through 180° in half a second is
A sound wave of frequency 210 Hz travels with a speed of 330 ms⁻¹ along the positive x-axis. Each particle of the wave moves a distance of 10 cm between the two extreme points. The equation of the displacement function (s) of this wave is (x in metre, t in second)
A string vibrates in its fundamental mode when a tension \(T_1\) is applied to it. If the length of the string is decreased by 25% and the tension applied is changed to \(T_2\), the fundamental frequency of the string increases by 100%, then \(\frac{T_2}{T_1}=\)
An object of height 3.6 cm is placed normally on the principal axis of a concave mirror of radius of curvature 30 cm. If the object is at a distance of 10 cm from the principal focus of the mirror, then the height of the real image formed due to the mirror is
Monochromatic light of wavelength 6000 Å incidents on a small angled prism. If the angle of the prism is 6°, the refractive indices of the material of the prism for violet and red lights are respectively 1.52 and 1.48, then the angle of dispersion produced for this incident light is