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In an AC series circuit, the instantaneous current is maximum when the instantaneous voltage is maximum. The circuit element connected to the source will be
The photons of energies twice and thrice the work function of a metal are incident on the metal surface. Then the ratio of maximum velocities of the photo electrons emited in the two cases respectively is
An electron beam is subjected to perpendicular electric and magnetic fields of 5 x 10-4 wbm-2 and 3 x 103 Vm-1 resectively. If there is no deflection, the velocity of electrons is
A 10 μ F capacitor is charged to a potential difference of 50 V and is connected to another uncharged capacitor in parallel. Now the common potential difference 20 volt. The capacitance of second capacitor is
The negative Zn pole of Daniell cell, sending a constant current through a circuit, decreases in mass by 0.13g in 30 min. If the electrochemical equivalent of Zn and Cu are 32.5 and 31.5 respectively, the increase in the mass of the positive Cu pole in this time is
Consider telecommunication through optical fibres. Which of the following statements is not correct
If the resistance of a conductor is 5 Ω at 50oC and 7 Ω at 100oC, then the mean temperature coefficient of resistance of the material is
A 6 V battery is connected to the terminals of a 3 m long wire of uniform thickness and of resistance 100 Ω. The potential difference between two points on the wire, separated by a distance of 50 cm will be
The current flowing through a wire depends on time as I = 3t2 + 2t +5. The charge flowing through the cross-section of the wire in time from t = 0 to t = 2 sec. is
Two resistors whose value are in ratio 2 : 1 are connected in parallel with one cell. Then ratio of power dissipated is
A generator at a utility company produces 100 A of current at 4000 V. The voltage is stepped up to 240000 V by a transformer before it is sent on a high voltage transmission line. The current in transmission line is
When the no. of turns in a coil is triplled, without any change in the length of coil, its self-inductance becomes
If the no. of turns of a solenoid are doubled and its length is halved keeping the area of cross-section same, then ratio of initial and final self-inductances will be
Eight dipoles of charges of magnitude e are placed inside a cube. The total electric flux coming out of the cube will be
Maxwell in his famous equation of electromagnetism introduced the concept of
A spherical shell of radius a with charge Q is expanded to radius b. The work done by the electric force in the process is
A charge of 5 C is given a displacement of 0.5 m. The work done in the process is 10 J. The potential difference between the two points will be
If an unchanged capacitor is charged by connecting it to a battery, then the amount of energy lost as heat is
Figure shows two large cylindrical shells having uniform linear charge densities + λ and - λ . Radius of inner aylinder is 'a' and that of outer cylinder is 'b'. A charged particle of mass m , charge q revolves in a circle of radius r. Then its speed 'V' is:
[Neglect gravity and assume the radii of both cylinders to be very small in comparison to their length]
A parallel plate capacitor filled with a dielectric of relative permittivity 5 between its plates is charged to acquire an energy E and isolated. If the dielectric is replaced by another of relative permittiviey 2, its energy becomes
E ∝ 1/k
In a radioactive disintegration, the ratio of initial number of atoms to the number of atoms present at an instant of time equal to its mean life is
To generate a power of 3.2 mega watt, the number of fissions of U235 per minute is (Energy released per fission = 200MeV, 1eV = 1.6 x 10-19 J)
When the light source is kept 20 cm away from a photo cell, stopping potential 0.6 V is obtained. When source is kept 40 cm away, the stopping potential will be
The threshold wavelength is 2000Å. The work function is
When triode is used as an amplifier, the phase difference between the input voltage and output is
To make P-type semiconductor, the impurity to be mixed with pure germanium will be
In Young's double slit experiment, two slits are made 5 mm apart and the screen is placed 2 m away. What is the fringe separation when light of wavelength 500 nm is used?
When Ge crystals are doped with phosphorus atom, then it becomes
The phase difference between two waves reaching a point is π/2 . If the individual amplitudes are 3mm and 4mm, the resultant amplitude is
If Young's double slit experiment of light, interference is performed in water, which one of the following is correct?
Ethyl alcohol can be used for preparation of which of the following?
The most reactive compound towards formation of cyanohydrin on treatment with KCN followed by acidification is
The organic compound which will answer the Fehling solution test is
The reagent(s) which can be used to distinguish acetophenone from benzophenone is (are)
Both methane and ethane can be prepared in one step by the reaction of
Hydrolysis of proteins in the presence of enzymes produces:
How many moles of Helium gas occupy 22.4 L at 0o C at 1 atm. pressure?
The hormone which controls the process like burning of fats, proteins and carbohydrates to liberate energy in the body is
Thyroxine is a hormone secreted by thyroid gland.
This hormone controls various biochemical reactions involving burning of proteins carbohydrates, fats to release energy.
Which of the following compounds is responsible for the transmission of heredity characters?
An alkyl cyanide forms an amide when it is treated with
In which of the following, the number of carbon atoms does not remain same when carboxylic acid is obtained by oxidation
A colourless liquid at room temperature reacts with soda lime to form sodium salt of carboxylic acid and ammonia gas.The liquid is
1 mole of N₂ and 2 moles of H₂ are allowed to react in a 1 dm3 vessel. At equilibrium 0.8 mole of NH₃ is formed. The concentration of H₂ in the vessel is
In a reversible reaction, two substances are in equilibrium. If the concentration of each one is reduced to half, the equilibrium constant will be
In which of the following neutralization reaction, the heat of neutralisation will be highest?
Given C(s) + O₂(g) → CO₂(g) ; ∆H = −395kJ, S(s) + O₂(g) → SO₂(g);∆H = −295kJ , CS₂(l) + 3O₂(g) → CO₂(g) + 2SO₂(g) ; ∆H = −1110kJ. The heat of formation of CS₂(l) is
In the presence of acid, the hydrolysis of methyl cyanide gives
Atomic numbers of Cr and Fe are respectively 24 and 26. Which of the following is paramagnetic?
Cr(CO)6 → Cr0 [Ar]3d6 4s0
no unpaired electron
[Cr(NH3)6]3+ → Cr3+ [Ar]3d3
Ammonia is a weak field ligand there are three unpaired electrons present
Fe(CO)5 → Fe0 [Ar]3d6 4s2
CO is a strong field ligand, therefore
[Fe(CN6)]4- → Fe2+ [Ar]3d3
CN- is a strong field ligand, therefore
The standard reduction potentials of Ag, Cu, Co and Zn are 0.799, 0.337, -0.277 and -0.762 V respectively. Which of the following cells will have maximum cell EMF?
Purification of silicon element used in semiconductors is done by
Air at sea level is dense. This is a practical application of
Fill in the blank with appropriate word.
Kavita.......a sum of Rs. 200 out of the bank every Monday
Out of the given alternatives, choose the one which can be substituted for the given capitalised word.
Many people CALLED ON the minister when he was ill.
Improve the sentence by choosing best alternative for capitalised part of the sentence.
ANY ABLE BODIED MAN eligible for the job.