The colour of light which is scattered the most by the atmospheric molecules is

An external voltage is applied across a diode such that the n-side is positive and the p-side is negative. As a result,
(A) the barrier height decreases
(B) the barrier height increases
(C) the depletion region widens
(D) the depletion region width decreases
(E) no change in barrier height
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The colour of the third band of a colour coded carbon resistor of resistance \(2.3 \times 10^2 \Omega\) would be

What is the ratio of the frequencies of the long wavelength limits of Lyman and Balmer series of hydrogen spectrum ?

A moving coil galvanometer has a coil of effective area \( A \), number of turns \( N \). The magnetic field \( B \) is radial. If current \( I \) is passed through the coil, the torque acting on the coil is:

A point object is placed at a distance of 20 cm from a spherical lens of refractive index n=3/2 and the radius of curvature of each surface 10 cm. The distance of the image formed from the lens is

In a single slit experiment, a diffraction pattern is obtained on the screen for yellow light. What will be the effect on the diffraction pattern, if yellow light is replaced by X-rays?

Which among the following are coordination complexes?
(A) Mohr's salt
(B) Tetraamminediaquacobalt (II) ion
(C) Carnallite
(D) Potassium ferricyanide
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The nitrogen atom in amines is trivalent and possess an unshared pair of electrons. The geometry of trimethyl amine is __________

The instantaneous current from a a.c source is I = 10sin 314t The frequency of the source would be

If \(x, y, z\) are non-zero numbers, then the inverse of matrix \(\mathrm{A}=\left[\begin{array}{lll}x & 0 & 0 \\ 0 & y & 0 \\ 0 & 0 & z\end{array}\right]\) is

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Sodium dichromate \(Na _2 Cr _2 O _7\) and Potassium dichromate \(K _2 Cr _2 O _7\) are strong oxidizing agents; in acidic solution, its oxidising action can be represented as follows :
\(Cr _2 O _7^{2-}+14 H ^{+}+6 e^{-} \rightarrow 2 Cr ^{3+}+7 H _2 O \left( E ^{\circ}=1.33 V\right)\)
The chromates and dichromates are interconvertible in aqueous solution depending upon pH of the solution.
The chromate ion is tetrahedral whereas the dichromate ion consists of two tetrahedra sharing one corner with \(Cr - O - Cr\) bond angle of \(126^{\circ}\)
Potassium permanganate is prepared by fusion of \(MnO _2\) with an alkali metal hydroxide and an oxidising agent like \(KNO _3\).
This produces the dark green \(K _2 MnO _4\) which disproportionates in a neutral or acidic solution to give permanganate. It is a strong oxidizing agent. Hydrogen ion concentration of the solution plays
an important part in the reduction of permanganate to manganate, manganese dioxide and manganese(II) salt.
Potassium permanganate forms dark purple (almost black) crystals which are isostructural with those of \(KClO _4\).
The salt is not very soluble in water \((6.4 g / 100 g\) of water at 293 K ), but when heated it decomposes at 513 K .
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Read the passage carefully and answer the questions
The transition metals and their compounds are known for their catalytic activity. This activity is ascribed to their ability to adopt multiple oxidation states and to form complexes. Vanadium(V) oxide (in Contact Process), finely divided iron, and nickel (in Catalytic Hydrogenation) are some of the examples. Catalysts at a solid surface involve the formation of bonds between reactant molecules and atoms of the surface of the catalyst (first row transition metals utilise 3d and 4s electrons for bonding). This has the effect of increasing the concentration of the reactants at the catalyst surface and also weakening of the bonds in the reacting molecules (the activation energy is lowering). Also because the transition metal ions can change their oxidation states, they become more effective as catalysts.
\(TiCl_4 + Al(CH_3)_3\) is used as a catalyst in: