List of top Questions asked in VITEEE

A Zener diode has a contact potential of 1V in the absence of biasing. It undergoes Zener breakdown for an electric field of \(10^6\) V/m at the depletion region of p--n junction. If the width of the depletion region is \(2.5\,\mu m\), what should be the reverse biased potential for the Zener breakdown to occur?
\(^{234}\)U has 92 protons and 234 nucleons total in its nucleus. It decays by emitting an alpha particle. After the decay it becomes
A certain radioactive material \(_x^AX\) starts emitting \(\alpha\) and \(\beta\) particles successively such that the end product is \(_{Z-3}^{A-8}\)A. The number of \(\alpha\) and \(\beta\) particles emitted are respectively
The \(K_{\alpha}\) and \(K_{\beta}\) X-rays are emitted when there is a transition of electron between the levels
The radioactivity of a certain material drops to \(\frac{1}{16}\) of the initial value in 2 hours. The half-life of this radionuclide is
An observer 'A' sees an asteroid with a radioactive element moving away at a speed \(0.3c\) and measures the radioactive decay time to be \(T_A\). Another observer 'B' is moving with the asteroid and measures its decay time as \(T_B\). Then \(T_A\) and \(T_B\) are related as
Which phenomenon best supports the theory that matter has a wave nature?
If the speed of a wave doubles as it passes from shallow water into deeper water, its wavelength will be
An electron microscope is used to probe the atomic arrangements to a resolution of 5 \AA. What should be the electric potential to which the electrons need to be accelerated?
A light whose frequency is equal to \(6 \times 10^{14}\) Hz is incident on a metal whose work function is 2 eV. The maximum energy of the electrons emitted will be
Two beams of light will not give rise to an interference pattern, if
A slit of width `a' is illuminated with a monochromatic light of wavelength \(\lambda\) from a distant source and the diffraction pattern is observed on a screen placed at a distance `D' from the slit. To increase the width of the central maximum one should
A thin film of soap solution (\(n = 1.4\)) lies on the top of a glass plate (\(n = 1.5\)). When visible light is incident almost normal to the plate, two adjacent reflection maxima are observed at two wavelengths 420 nm and 630 nm. The minimum thickness of the soap solution is
The standard free energy change of a reaction is $\Delta G^{\circ}$ = - $115\,kJ$ at $298 \,K$. Calculate the equilibrium constant $k_p$ in $\log k_p$ $ (R = 8.314 \,Jk^{-1} mol^{-1}).$
Reaction of $PCl _{3}$ and $PhMgBr$ would give
Anisole is the product obtained from phenol by the reaction known as
When acetamide is hydrolysed by boiling with acid, the product obtained is :
When ethyl alcohol is heated with conc. $H_2SO_4$, the product obtained is :
Which will not go for diazotization ?
Three resistances of $4 \,\Omega$ each are connected as shown in figure. If the point $D$ divides the resistance into two equal halves, the resistance between point $A$ and $D$ will be
A solid sphere of radius $R_{1}$ and volume charge density $\rho=\frac{\rho_{0}}{r}$ is enclosed by a hollow sphere of radius $R_{2}$ with negative surface charge density $\sigma$, such that the total charge in the system is zero, $\rho_{0}$ is a positive constant and $r$ is the distance from the centre of the sphere. The ratio $\frac{R_{2}}{R_{1}}$ is
Let $y$ be the number of people in a village at time $t$. Assume that the rate of change of the population is proportional to the number of people in the village at any time and further assume that the population never increases in time. Then the population of the village at any fixed time $t$ is given by
Which of the following is not a characteristic of transition elements ?
The number of hydrogen atoms present in $25.6\, g$ of sucrose $\left( C _{12} H _{22} O _{11}\right)$ which has a molar mass of $342.3\, g$ is
Which of the following is ketohexose ?