The formation of rainbow is an example of

Which of the following statements related to Wheatstone Bridge are correct?
(A).The bridge is most sensitive when all the four resistances are of the same order
(B). The internal resistance of the cell and the resistance of the galvanometer affect the null point
(C). It does not involve measurement of current and potential difference
(D).Resistances of ammeters and voltmeters do not affect the measurements
Choose the correct answer from the options given below:

For transmitting a modulated signal of wave length \( \lambda \), the antenna should have minimum size:

A current of 5 A is passing through a metallic wire of cross-sectional area \( 5 \times 10^{-6} \text{ m}^2 \).
If the density of the charge carriers in the wire is \( 5 \times 10^{26} \text{ m}^{-3} \), the drift velocity of the electrons is:

In a series RLC circuit at resonance
(A) Impedance is maximum
(B) \( X_c = X_L \)
(C) Z = R
(D) \( \omega = \frac{1}{\sqrt{LC}} \)
Choose the correct answer from the options given below:

An infinite line of charge has a linear charge density of \(10^{-7} \text{ C m}^{-1}\). The magnitude of the force acting on a charge \(6.4 \times 10^{-19} \text{ C}\) kept at a distance of 8 cm from the line of charge is

In experimental arrangement to study photoelectric effect, here M, N, O and P respectively are

(A) Commutator
(B) Evacuated glass tube
(C) Quartz window
(D) Photosensitive plate
Choose the correct answer from the options given below:

Read the passage carefully and answer the questions.
Amines are considered to be derivatives of ammonia obtained by replacement of hydrogen atoms with alkyl or aryl groups. They are usually prepared from nitro compounds, halides, amides, imides etc. The presence of hydrogen bonding influences its physical properties. In alkylamines, a combination of electron releasing steric and hydrogen bonding factors influences the stability of substituted ammonium cations in protic polar solvents and thus affects the basic nature of amines. Alkyl amines are found to be stronger bases than ammonia which is more basic than water. Primary and secondary amines are engaged in intermolecular association due to hydrogen bonding. This intermolecular association is more in primary amines than in secondary amines. Tertiary amines do not have intermoleulcar association due to the absenceof hydrogen atom available for hydrogen bonding. Thus, the boiling point of amines depends on hydrogen bonding. In aromatic amines, electron releasing and withdrawing groups increase and decrease their basic character. Aryl diazonium salts usually obtained from arylamine undergo replacement of the diazonium group with a variety of nucleophile. Their coupling reaction of aryl diazonium salts with phenol or arylamine results in formation of dyes.
Which of the following compounds will not undergo azo coupling with benzene diazonium chloride?

If \(\vec{a}, \vec{b}\) and \(\vec{c}\) are three vectors such that \(\vec{a}+\vec{b}+\vec{c}=\overrightarrow{0},|\vec{a}|=7,|\vec{b}|=3\) and \(|\vec{c}|=5\), then angle between \(\vec{b}\) and \(\vec{c}\) is

The condition where one species is harmed whereas the other is unaffected is called.

A symmetric double convex lens of power 4D is cut in two halves by plane perpendicular to the principal axis. The power of each half is :

If A and B are two matrices of order 2 × 2 such that A is a symmetric matrix and B is a skew-symmetric matrix, then:

In Vallisneria, the pollination is carried by: