The velocity of light in diamond, glass and water decreases in the following order :

When copper and germanium are cooled from room temperature to 100 K, then :

The elements which may be considered for an ideal inductor as a solenoid,
(A) which is made of a thick wire
(B) which has negligible resistance
(C) which has a sufficiently large inductance
(D) which is made of a thin wire
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A small telescope has an objective lens of focal length 120 cm and an eyepiece of focal length of 5.0 cm. The magnifying power of telescope for viewing distant objects in normal adjustment is

Identify the correct statement(s) among the following:
(A) The time taken by a light wave is \( 5 \times 10^{-9} \text{ s} \) to travel a thickness of 1 cm of glass having refractive index 1.5.
(B) Two similar waves of amplitude 3 mm and 5 mm reach a point in the same phase. The resultant amplitude will be 8 mm.
(C) Two waves of amplitude 2 mm each reach a point with a phase difference of \( \pi/2 \). The resultant amplitude is zero.
(D) If one of the slits is closed in Young's double slit experiment, the interference pattern will disappear.
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Below given are some statements about electronic devices:
(A) Diodes can be used for rectifying an ac voltage.
(B) For semiconductors, band gap energy \( E_g > 3 \, eV \).
(C) By changing the external applied voltage, junction barriers can be changed.
(D) p-n junction is the 'key' to all semiconductor devices.
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Electromagnetic wave travels with speed of \(2.0 \times 10^8 m / s\) in any medium of relative permeability ( \(\mu_r\) ) 1.5. Find the relative permittivity of the medium ( \(\epsilon_r\) )

If a man with blood group A marries a woman with blood group AB. Which of the following blood group will never be found in their children?

Formaldehyde undergoes the Cannizzaro reaction because:
(A) It has alpha-hydrogen atom.
(B) It does not have alpha-hydrogen atom.
(C) It does not undergo self-oxidation and reduction on heating with concentrated alkali.
(D) It undergoes self-oxidation and reduction on heating with concentrated alkali.
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Answer the question on the basis of passage given below :
Aldehydes and ketones represent two essential classes of organic compounds which are extensively used in the synthesis of a wide variety of other organic molecules. Due to the inherent polarity of the central carbonyl group, these substances readily undergo nucleophilic addition reactions. Broadly speaking, these addition reactions can be categorized into two types: one in which simple addition of the nucleophilic reagent occurs across the \(> C = O\) bond, and the second type where the initial addition is subsequently followed by the elimination of a water molecule. A variety of ammonia derivatives, including hydroxylamine, hydraaine, phenylhydraxine, 2,4-dinitroplhemylhdrasine, and semicarbaside, all belong to this second category of reactions. These specific derivatives are fundamentally used for the identification and definitive characterization of aldehydes and ketones. Significantly, both types of nucleophilic addition reactions are strongly influenced by both steric and electronic factors. As a general rule, aliphatic aldehydes exhibit higher reactivity compared to aromatic aldehydes. The aliphatic aldehydes demonstrate the ability to reduce both Fehling's solution and Tollen's reagent, whereas aromatic aldehydes are limited to reducing only Tollen's reagent. In a similar manner to aldehydes, aromatic ketones are observed to be less reactive than aliphatic ketones towards all nucleophilic addition reactions. In a separate context, phenols and carboxylic acids both exhibit acidic properties in nature. Both classes of compounds readily dissolve in NaOH solution and cause blue litmus to turn red. However, carboxylic acids stand out as much stronger acids than phenols and thus can decompose sodium bicarbonate \(\left( NaHCO _3\right)\) with the distinct evolution of \(CO _2\) gas, a reaction which phenols do not undergo. It is important to note that both electron- donating and electron- withdrawing substituents significantly influence the acid strength of both aliphatic as well as aromatic carboxylic acids. Furthermore, unlike all other common aliphatic acids, formic acid uniquely possesses reducing properties and simultaneously does not display the typical reactions characteristic of the allyl group.
Which of the following statement(s) is/are correct?
A. Aldehydes give positive test with Tollen's reagent.
B. Ketones give positive test with Fehling's solution
C. Ketones do not react with Fehling's solution.
D. Aldehydes with Schiff's reagent restore pink colour
E. Ketones with Schiff's reagent restore pink colour.
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If \(\left|\begin{array}{cc}3 x & 7 \\ 4 & x\end{array}\right|=\left|\begin{array}{cc}6 & -2 \\ 4 & 2\end{array}\right|\), then the value of \(x\) is :

Match List-l with List-ll

List-l(Materials)	List-lI(Conductivity ( \(\mathrm{S} \mathrm{m}^{-1}\) ))
(A) Gold	(I) \(1.0 \times 10^{-16}\)
(B) Germanium	(II) \(1.2 \times 10\)
(C) Glass	(III) \(4.5 \times 10^3\)
(D) Graphite	(VI) \(2.0\)

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Read the passage carefully and answer the Questions
The term vitamin was coined from the word vital +amine since the earlier identified compounds had amino groups. Later work showed that most of them didn't contain amino groups, so the letter "e" was dropped and ther term vitamin is used these days.
Vitamins are classified into two groups depending upon their solubility in water or fat. Fat soluble vitamins are soluble in fat and oils but insoluble in water. They are stored in liver and adipose (fat storing) tissues. Water-soluble vitamins are soluble in water. They must be supplied regularly in the diet as they are readily excreated in urine.
What are the sources of Vitamin B12?