Two metals, X and Y have work functions, 4 eV and 10 eV, respectively. The ratio of threshold wavelengths of metal X to metal Y is

A source of electromagnetic wave of 400 W produces \(10^{20}\)photons per second. Identify the part of the electromagnetic spectrum to which these radiations belong:

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

The S.I unit of mutual inductance, the 'henry' can be written as

A diode having potential difference 0.5 V across its junction which does not depend on current, is connected in series with a resistance of \( 20 \Omega \) across a source. If 0.1 A current passes through the resistor, the voltage across the source is :

A monochromatic source emitting light of wavelength 600 nm has a power output of 66 W. The number of photons emitted by the source in 2 minutes is: (Given: \( h = 6.6 \times 10^{-34} \text{ Js} \))

Match List-I with List-II

List-I (Law/Rule)	List-II (Application)
(A) Faraday's law	(l) Determines direction of force on a current carrying wire in a magnetic field
(B) Lenz's law	(II) Obeys principle of energy conservation
(C) Fleming's right-hand rule	(III) Determines direction of induced current
(D) Fleming's left-hand rule	(IV) Electromagnetic Induction

Choose the correct answer from the options given below :

\(\int_{3 \pi / 8}^{\pi / 8} \frac{\tan ^{2025} x}{\tan ^{2025} x+\cot ^{2025} x} d x\) is equal to

The dipole moment of a circular loop carrying a current I is m and the magnetic field at the centre of the loop is \( B_1 \). When the dipole moment is made three times by keeping the current I same, the magnetic field at the centre of the loop becomes \( B_2 \). The ratio of \( B_1 \) and \( B_2 \) is:

The solution set of the inequality \(3 x+5 y<15\) is :

If the length of a wire is doubled while keeping its material and cross-sectional area same, the resistance of the wire

Which of the following does NOT serve as biofertilizer in paddy field?

Read the following passage carefully and answer the given questions.
Biofertilisers
Biofertilisers are organisms that enrich the nutrient quality of the soil and their main sources are bacteria, fungi and cyanobacteria. You have studied about the nodules on the roots of leguminous plants formed by the symbiotic association of Rhizobium. These bacteria can fix atmospheric nitrogen into organic forms. Other bacteria can also fix atmospheric nitrogen while free-living in the soil (examples Azospirillum and Azotobacter). Fungi are also known to form symbiotic associations with plants (mycorrhiza). Many members of the genus Glomus form mycorrhiza. Plants having such associations show other benefits also, such as resistance to root-borne pathogens, tolerance to salinity and drought, and an overall increase in plant growth and development. Cyanobacteria are autotrophic microbes widely distributed in aquatic and terrestrial environments many of which can fix atmospheric nitrogen, e.g. Anabaena, Nostoc, Oscillatoria, etc. In paddy fields, cyanobacteria serve as an important biofertiliser. Blue green algae also add organic matter in to the soil and increase its fertility. Currently, in our country, a number of biofertilisers are available commercially in the market and farmers use these regularly in their fields to replenish soil nutrients and to reduce dependence on chemical fertilisers.
Which one of the followings is not a symbiotic microbe?