List of top Questions asked in KCET

A wafer of pure germanium crystal has two parts X and Y. The end X is obtained by doping with arsenic and Y with indium. It is connected to a battery as shown in the figure. Which of the following statements is correct?
In which of the following figures, diode is reverse biased?
An n-type and p-type semiconductor can be obtained by respectively doping pure silicon with
An electron transition takes place from excited state to ground state in hydrogen atom, then
Bohr's second postulate implies quantisation of
The radius of first orbit in hydrogen atom is 5.3 \(\times\) 10\(^{-11}\) m. The kinetic energy E\(_K\), potential energy E\(_P\) and total energy E\(_T\) of electron in first orbit are
In Young's double slit experiment, how many maxima can be seen on a screen (including central maxima) if d = \(\frac{5\lambda}{2}\) (where \(\lambda\) is wavelength of light and d is distance between the two slits).
What range of electromagnetic spectrum is considered as light?
The critical angle for a monochromatic light going from medium A to medium B is \(\theta\). If the speed of light in medium A is V, then the speed of light in medium B is
The incorrect statement about refractive index for a pair of media is
The direction of a ray of light incident on a concave mirror is shown by PQ, while direction in which the ray would travel after reflection is shown by four rays marked as A, B, C and D as shown in the figure. Which of the four rays correctly shows the direction of the reflected ray?
With reference to the figure shown below, match the following:
Match the following Maxwell's equations: (The symbols used here have their usual meanings)
A light bulb rated 100 W is connected to an AC source of 220 V, 50 Hz. The rms current through the bulb is
In a circuit containing a pure resistor connected to an AC source,
In the figure shown, the conductor PQ of length \(l\) is moved from \(x = 0\) to \(x = b\) and then up to \(x = 2b\) with a constant velocity \(\vec{v}\). A uniform magnetic field \(\vec{B}\) is perpendicular to the plane of the paper and extends from \(x = 0\) to \(x = b\) and it is zero from \(x>b\). The magnitude of emf induced in the conductor is
In Faraday-Henry's experiment, a coil is connected to a galvanometer. For the deflection of pointer in the galvanometer, which of the following statement/s is/are WRONG?
The pointer in the galvanometer deflects -
(a) When the bar magnet is moved towards the stationary coil along its axis
(b) When the bar magnet is moved away from the stationary coil along its axis
(c) When the coil is moved towards the stationary bar magnet along its axis
(d) When the coil and the magnet are moved without relative motion between them
Variation of photoelectric current with anode potential is shown below. Choose the correct option (V\(_0\) = stopping potential).
Work function of the metal is
Pick out the WRONG statements about magnetic substances (\(\chi\) = magnetic susceptibility) (\(\mu_r\) = relative permeability).
I. Substances with \(-1 \le \chi<0\) are diamagnetic
II. Substances with \(\chi \gg 1\) are paramagnetic
III. Substances with \(\chi \ll 1\) are ferromagnetic
IV. Substances with \(\mu_r \gg 1\) are ferromagnetic
If a paramagnetic bar is brought near a bar magnet, then it is
Two identical circular current loops carrying equal currents are placed with their axes inclined at 45\(^{\circ}\) to each other as shown in the figure. The resultant magnetic field at P is
Biot-Savart law indicates that an electron moving with a velocity \( \vec{V} \) produces a magnetic field \( \vec{B} \) around it such that
A proton, an electron and an \(\alpha\)-particle enter at right angles to a uniform magnetic field with the same velocity. If R\(_p\), R\(_e\) and R\(_\alpha\) are the radii of circular paths of these particles, then
A point charge is placed in a moving train. A passenger A sitting in the train and person B on the ground observe the fields due to this charge. Then