List of practice Questions

ΔS would be negative for which of the following reactions? 
(I) \( {CaCO}_3(s) \rightarrow {CaO}(s) + {CO}_2(g) \) 
(II) \( {Ag}^+(aq) + {Cl}^-(aq) \rightarrow {AgCl}(s) \)
(III) \( {N}_2(g) + 3{H}_2(g) \rightarrow 2{NH}_3(g) \)
Choose the correct answer from the codes given below:

Which of the following molecule has the most polar bond?
The unit of an universal constant is cm\(^{-1}\). What is the constant?
The thickness of the depletion layer on either side of the p-n junction is of the order of
If the conductivity of the material lies in the range \(10^2 - 10^8 \, \Omega^{-1}m^{-1}\), then it is a
An external voltage \( V \) is supplied to a semiconductor diode having built-in potential \( V_0 \). The effective barrier height under forward bias is
In gamma emission, the nucleus emits
The energy required to excite the hydrogen atom from its first excited state to second excited state is:
A particle having mass 2000 times that of an electron travels with a velocity thrice that of the electron. The ratio of the de Broglie wavelength of the particle to that of the electron is
If the power of a lens is +4 D, then the lens is a
The radiations used in LASIK eye surgery are:
The reactance of an induction coil of 4 H for a dc current (in \( \Omega \)) is:
When a current passing through a coil changes at a rate of 30 A s\(^{-1}\), the emf induced in the coil is 12 V. If the current passing through this coil changes at a rate of 20 A s\(^{-1}\), the emf induced in this coil is:
Which one of the following statement is INCORRECT?
If a cell of 12 V emf delivers 2 A current in a circuit having a resistance of 5.8 \(\Omega\), then the internal resistance of the cell is:
n number of electrons flowing in a copper wire for 1 minute constitute a current of 0.5 A. Twice the number of electrons flowing through the same wire for 20 s will constitute a current of:
The resistance of a wire at 0 °C is 4 \(\Omega\). If the temperature coefficient of resistance of the material of the wire is \(5 \times 10^{-3} / ^\circ C\), then the resistance of a wire at 50 °C is:
If the fundamental frequency of the stretched string of length 1 m under a given tension is 3 Hz, then the fundamental frequency of the stretched string of length 0.75 m under the same tension is:
A wave with a frequency of 600 Hz and wavelength of 0.5 m travels a distance of 200 m in a time of:
All real gases behave like an ideal gas at:
When heat is supplied to the gas in an isochoric process, the supplied heat changes its:
The stress required to produce a fractional compression of 1.5% in a liquid having bulk modulus of \( 0.9 \times 10^9 \, {Nm}^{-2} \) is:
The terminal velocity of a small steel ball falling through a viscous medium is:
The force of gravity is a:
The escape speed of the moon when compared with escape speed of the earth is approximately: