The ground state energy of hydrogen atom is -13.6 eV . When its electron is the first excited state , its excitation energy is
Excitation energy = Ef - Ei
= - 3.4 - (-13.6) = 10.2 eV
A transformer connected to 220 volt line shows an output of 2 A at 11000 volt. The efficiency is 100%. The current drawn from the line is
Sodium has body centred packing. Distance between two nearest atoms is 3.7 Å . The lattice parameter is:
The capacity of an isolated conducting sphere radius R is propotional to
The internal resistance of a primary cell is 4 Ω. It generates a current of 0.2 A in an external resistance of 21 Ω. The rate at which chemical energy is consumed in providing the current is
If sky wave with a frequency of 50 MHz is incident on D-region at an angle of 300, then angle of refraction is
Conductivity increases in the order of
Consider the following statements
Assertion (A) : In a simple battery circuit, the point of the lowest potential is positive terminal of the battery
Reason (R) : The current flows towards the point of the higher potential, as it does in such a circuit from the negative to the positive terminal
(where x is the displacement)
Of these statements
A battery of e.m.f. 6 V and internal resistance 4 Ω is connected to a external resistor. If the current in the circuit is 0.5 A, then terminal voltage of battery when the circuit is closed, is
The resistance of a wire is R. If the length of the wire is doubled by stretching, then the new resistance will be
Which of the following is a correct statement?
A transformer is used to light a 100W and 110V lamp from a 220V mains. If the main current is 0.5A, the efficiency of the transformer is approximately
Energy needed to establish an alternating current I in a coil of self inductance L is
E = 1/2 LI2
An alternating potential V =V0 sin ωt is applied across a circuit. As a result, the current I=I0 sin (ωt-π/2) flows in it. The power consumed in the circuit per cycle is
P = Eν Iν cosØ = Eν Iν cos 90 = zero.
Heat radiations propagate with the speed of
A charge Q is placed at the corner of a cube. The electric flux through all the six faces of the cube is
Two charges -10 C and + 10 C are placed 10cm apart. Potential at the centre of the line joining two charges is
n small drops of same size are charged to V volt each. They coalesce to form a bigger drop. The potential of the bigger drop is
The capacity of a condenser 'A' is 10 μ F and it is charged by a battery of 100V. The battery is disconnected and the condenser is connected to a condenser 'B'. The common potential is 40V. The capacity of 'B' is
Two point charges of +4 μC and -6 μC are separated by a distance of 20 cm in air. At what point, on the line joining the two charges from charge +4 μC, the electric potential will be zero?
Van de Graaff electrostatic generator is based on
A beam of light travelling along x-axis is described by the electric field Ey = 600 V m-1 sin ω(t − x ∕ c) then maximum magnetic force on a charge q = 2e, moving along y-axis with a speed of 3.0 x 107 m s-1 is e = 1.6 x 10-19C
A radioactive element has a half life of 15 years. The fraction that will decay in 30 years is
In the following reaction the energy released is 4 1H1 → 2He4 + 2 +1e0 + energy
The energy released per fission of a U235 nucleus is around
A mercury vapour lamp is the example of
Einstein's work on the photoelectric effect provied support for the equation
The maximum wavelength of radiation that can produce photoelectric effect in certain metal is 200 nm. The maximum kinetic energy acquired by electron due to radiation of wavelength 100 nm will be
The magnifying power of a simple microscope M is given by
Region without free electrons and holes in a p-n junction is
A piece of Aluminium and Germanium each are cooled from T1K to T2K. The resistance of
A zener diode works on the principle of
Which of the following statement is correct?
With rise in temperature, the specific resistance of semiconductors
In a P-type semiconductor
When a p-n junction diode is reverse biased, the flow of current across the junction is mainly due to
If ratio of amplitude of two waves is 4:3, then ratio of maximum and minimum intensity is
The sun is rotating about is own axis. The spectral lines emitted from the two ends of its equator, for an observer on the earth, will show
Who was the first to demonstrate the phenomenon of interference of light?
When light wave suffer reflection at the interface between air and glass, the change of phase of reflected wave is equal to
n-Propyl alcohol and isopropyl alcohol can be chemically distinguished by which reagent
Aldol condensation will not be observed in
Which of the following compounds containing carbonyl group will give coloured crystalline compound with
During reduction of carbonyl compounds by hydrazine and KOH, the first intermediate formed is
When ethylbromide and n-propyl bromide is allowed to react with sodium, in ether, they form
Ozonolysis of C₇H₁₄ gave 2-methyl-3-pentanone toluene. The alkene is
Homolytic fission of C - C bond in ethane gives an intermediate in which carbon is
Homolytic fission of C — C bond gives free radicals in which carbon is sp2 hybridised.
4.4 g of an unknown gas occupies 2.24 L of volume at standard temperature and pressure. The gas may be
The disaccharide present in milk is
An example of amino acid containing benzene ring is
Ethyl isocyanide on acidic hydrolysis generates
Enzymes belongs to the class of compounds
Calcium acetate when dry distilled gives
The reaction N₂ + O₂ → 2NO is endothermic . The forward reaction is
A vessel at equilibrium, contains SO₃, SO₂ and O₂. Now some helium gas is added, so that total pressure increases while temperature and volume remain constant. According to Le-Chatelier's principle, the dissociation of SO₃
A compound with molecular mass 180 is acylated with CH3COCl to get a compound with molecular mass 390. The number of amino groups present per molecule of the former compound is:
Aspirin is an acetylation product of
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
The IUPAC name of dextro K₃[Ir(C₂O₄)₃] is
What is the entropy change (in J K-1 mol-1), when one mole of ice is converted into water at 00C? (The enthalpy change for the conversion of ice to liquid water is 6.0kJ mol-1 at 00C)
Given the bond energies of N ≡ N , H − H and N − H bonds as 941.5, 433 and 391 kJ mole-1 respectively, the enthalpy of reaction N 2 g + 3 H2 g → 2 NH3 g is
Enthalpy of reaction = ∑ bond energyreactant - ∑ bond energyproduct
= bond energy (n2) + 3 x (bond energy) (h2) - 2 x (bond energy) (NH3)
= 941.5 + (3 x 433) - 2 x 3 x 391
= 2240.5 - 2346 = 105.4 ≅ -105kJ
IUPAC name of (CH3)2 CH CH2 CH2 Cl is
Compound A has a molecular formula C₇H₇NO on treatment with Br₂/KOH, A gives an amine B which respond to carbylamine test. B on diazotisation and coupling with phenol give an azo dye. A can be
In a galvanic cell, the electrons flow from
Acetaldoxime reacts with P₂O₅ to give
What will be the weight of silver deposited on passing 965 coulombs of electricity in solution of AgNO₃ ?
The hydrid state of Ni in Ni(CO)₄ is
Cell Ni|Ni2+ (1M)||Cl- (1M)| + Cl2 Pt
EMF of the cell = ECathode - EAnode
Or E = ERight - Eleft
= 1.36 - (- 0.25)
= 1.36 + 0.25
EMF = +1.61 V
Which of the following process is not used for the purification of solid impurites?
Acetic anhydride reacts with diethyl ether in the presence of anhydrous AlCl₃ to give
The element that does not form a monoxide is
At higher altitude the boiling point of water lowers because
Of the following compounds, the most acidic is
Which one of the following compounds does not exist ?
Carbon is in the lowest oxidation state in
Coordination number of Na⁺ in NaCl is
Compound A below
In chemisorption, adsorption decreases after increase due to
Which of the following pairs of ions are colourless?
CuCl₂ and CuBr₂ exist as
Find the Antonym of GATHERED
Fill in the blank with appropriate word.
However, the group's long term stretegy is to.........on core sector businesses connected with infrastructure and energy
Find the Syonym of ARTIFACT
Choose the alternative which best expresses the meaning of the idiom/phrase.
Feathering one's nest
Improve the sentence by choosing best alternative for capitalised part of the sentence.
When Rip Van Winkle awoke from his long sleep, he asked where I AM.