The work function for a metal surface is 8.28 eV . The threshold wavelength for this metal surface is :

A long straight wire of radius 'a' carries a steady current 'I'. The current is uniformly distributed across its area of cross-section. The ratio of magnitude of magnetic fields \( B_1 \) at a distance a/2 and \( B_2 \) at a distance 2a from the axis of the wire is :

The resistivity of an iron wire is \( 10 \times 10^{-8} \, \Omega \text{ m} \). The resistance of an iron wire is \( 5 \, \Omega \). If its length as well as thickness is doubled then its resistivity will be :

Two slits are made 0.8 mm apart and the screen is placed 1.5 m away. What should be the width of each slit to obtain 8 maxima of the double slit pattern within the central maximum of the single slit pattern?

The size of the atom is of the order of:

The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than 2480 nm is incident on it. The band gap for the semiconductor is :

If a proton is brought towards an electron from infinity, the potential energy of the system will

Match List I with List - II.

List - I	List - II
(A) L.C. Oscillation	(I) Inductor supplied with AC
(B) \( Q = \frac{\omega_o L}{R} \)	(II) \( \frac{d^2q}{dt^2} + \frac{1}{LC}q = 0 \)
(C) Voltage leads current	(III) \( \frac{i_p}{i_s} = \frac{V_s}{V_p} \)
(D) Transformer	(IV) Sharpness of resonance curve

Choose the correct answer from the options given below :

The point on the curve \(y=\cos x-1, x \in\left[\frac{\pi}{2}, \frac{3 \pi}{2}\right]\) at which tangent is parallel to the x-axis is:

Let \(A\) and \(B\) are square matrices of order 3 such that \(A+B=\left[\begin{array}{ccc}2 & -2 & -4 \\ -1 & 3 & 4 \\ 1 & -2 & -3\end{array}\right]\). If \(A\) is a symmetric matrix, then the value of \(|B|\) is:

Read the passage carefully and answer the Questions
Haloalkanes undergo nucelophilic substitution reactions owing to the polarity of CX bond. The nucleophile reacts with the haloalkane on the carbon possessing a partial positive charge holding the halogen atom. The halogen atom \(X\) is replaced by a nucleophile. Depending on the kinetics and mode of bond breaking, the mechanism can be either SN1 or SN2 reaction. The rate of SN1 reaction is governed by the stability of carbocation and in SN2 reaction, the rate of reaction is governed by steric factor. Chirality is the main factor in both SN1and SN2. In SN1 reaction, the chirality of alkyl halide is accompanied by racemization of the product, while in SN2 reaction, the product is characterized by inversion of configuration. The structure of alkyl halide and the nature of the solvent also governs the mechanism of the substitution.
Which of the following compound will undergo \(S_N 1\) reaction readily?

If 'n' identical resistors, each of value 'R' are first connected in series to a battery of emf 'E' and internal resistance 'R', the current drawn is 'I'. Now if they are connected in parallel, then the current drawn is '5 I'. The value of n is

Which of the following properties are related to the complex \(\left[ Fe \left( H _2 O \right)_6\right]^{3+}\) ?
(A) Paramagnetic
(B) Number of unpaired electrons are five
(C) \(d ^2 sp ^3\) hybridisation
(D) \(H _2 O\) is a strong field ligand
Choose the correct answer from the options given below :