Choose the correct answer :
1. The minimum energy that must be possessed by photons in order to produce the photoelectric effect with platinum metal is
[Given The threshold frequency of platinum is 1.3 × 1015 s–1 and h = 6.6 × 10–34 Js.]
Given below are two statements.
Statement-I: During electrolytic refining, blister copper deposits precious metals.
Statement-II: In the process of obtaining pure copper by electrolysis method, copper blister is used to make the anode.
In the light of the above statements, choose the correct answer from the options given below.
The number of bridged oxygen atoms present in compound B formed from the following reactions is
\(PB(NO_3)^2→(673 K)→A+PBO+O_2A→(Dimerise)B.\)
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Polluted water may have a value of BOD of the order of 17 ppm.
Reason R: BOD is a measure of oxygen required to oxidise both the bio-degradable and non-biodegradable organic material in water.
In the light of the above statements, choose the most appropriate answer from the options given below.
Assertion A: A mixture contains benzoic acid and naphthalene. The pure benzoic acid can be separated out by the use of benzene.
Reason R: Benzoic acid is soluble in hot water.
In the given reaction
‘A’ can be
The major product formed in the following reaction, is
The system of equations
–kx + 3y – 14z = 25
–15x + 4y – kz = 3
–4x + y + 3z = 4
is consistent for all k in the set
A baseband signal of 3.5 MHz frequency is modulated with a carrier signal of 3.5 GHz frequency using amplitude modulation method. What should be the minimum size of antenna required to transmit the modulated signal?
Two identical thin biconvex lenses of focal length 15 cm and refractive index 1.5 are in contact with each other. The space between the lenses is filled with a liquid of refractive index 1.25. The focal length of the combination is ___ cm.