Daily life phenomena based on scattering of light are
(A) Blue colour of sky
(B) Clouds appearing white
(C) Twinkling of stars
(D) Danger signals being red
Choose the correct answer from the options given below:

Eight charged water droplets, each of radius 1 mm and carrying a charge \( 5 \times 10^{-10} \text{ C} \), coalesce to form a single drop. The potential of the bigger drop is.

A point source of light is placed at a distance twice the focal length of a converging lens. If the focal length of the lens is f, the intensity of the image of light source on the other side of the lens will be maximum at

In a series combination of capacitors connected across a battery

In a series L, C and R circuit with an ac source of frequency \( \omega \), the current leads the voltage by \( \pi/4 \). The value of capacitance C will be

Two sources of equal emf are connected in series. This combination is connected to an external resistance R.
The internal resistance of two sources are \( r_1 \) and \( r_2 \) (\( r_2 > r_1 \)).
If the potential difference across the source of internal resistance \( r_2 \) is zero, then R equals to:

A moving coil galvanometer has 100 equal divisions. Its current sensitivity is 20 divisions per mA and voltage sensitivity is 4 divisions per mV. To convert it into a voltmeter in which each division reads 1 V, the resistance needed to be connected in series with the coil will be :

Which of the following statements are correct?
(A) All of electrostatics is basically a consequence of Coulomb's law and the super position principle.
(B) A change producing the electric field is a test change.
(C) Electric and magnetic fields are regarded as physical entities.
(D) In water molecule centres of positive changes and negative changes do not coincide.
(E) Electrostatic field lines cannot form closed loops.
Choose the correct answer from the options given below :

On which of the following components, the pattern and behavior of the data in any time series is based?
(A). Secular trend component
(B). Seasonal component
(C). Cyclical component
(D). Regular component
Choose the correct answer from the options given below :

In alcohols, C-O-H bond angle is:

Arrange the following in increasing order of their basic strength
(I) \(C_6H_5NH_2\)
(II) \(C_2H_5NH_2\)
(III) \(NH_3\)

Microbe responsible for converting milk to curd is :

Answer the question on the basis of passage given below :
Formaldehyde is the first member of the aldehydic series. It is present in green leaves of plants where its presence is supposed to be due to the reaction of \(CO_2\) with water in the presence of sunlight and chlorophyll. Commercially, formaldehyde is obtained by the controlled oxidation of methane in the presence of molybdenum oxide (\(MoO\)) acting as a catalyst. Formaldehyde is a constituent of a number of polymers also called resins. These are non volatile solids or semi solids which are obtained directly from certain plants and can be synthesized in the laboratory.
Question: Formaldehyde on reaction with benzaldehyde in basic medium gets converted to: