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A proton and an α - particle enter into a region of uniform electric field. The ratio of the force on proton to that on α - particle is
The number of electrons emitted by a surface exposed to light is directly propotional to
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
A steady current of 1.5A flows through a copper voltameter for 10 min. If the electrochemical equivalent of copper is 30 x 10-5g C-1 , the mass of copper deposited on the electrode will be
In short wave communication waves of which of the following frequencies will be reflected back by the ionospheric layer having electron density 1011 per m-3?
N max = 1011per m-3
Identify that set in which all the three sustances are good conductors of electricity
The emf of a Daniel cell is 1.08V. When the terminals of the cells are connected to a resistance of 3 Ω , the potential difference across the terminals is found to be 0.6V. Then the internal resistance of the cell is
Three unequal resistors in parallel are equivalent to resistance 1 Ω . If two of them are in the ratio 1 : 2 and if no resistance value is fractional, the largest of the three resistances in ohms is
In a meter bridge, with an unknown resistance the standard resistance in the left gap is 6 Ω. If ratio of balancing lengths of meter bridge wire is 2:3, then the value of unknown resistance is
The primary and secondary coils of a transformer have 50 and 1500 turns respectively. If the magnetic flux φ linked with the primary coil is given by φ = φ 0 + 4t, where φ is in weber, t is time in second and φ 0 is a constant, the output voltage across the secondary coil is
No. of turns across primary Np = 50
Number of turns across secondary Ns = 1500
Magnetic flux linked with primary, Φ = Φ0 + 4t
∴ Voltage across the primary,
In an A.C. circuit, the current is i = 5 sin (100t - π/2) amp and the a.c. potential is V = 200 sin (100t) volt. Then, the power consumption is
If 2.2 kW power is transmitted through a 10 Ω line at 22000 V, the power loss in the form of heat will be
A point charge q is placed at a distance a/2 directly above the centre of a square of side a. The electric flux through the square assuming it to be one face 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
Equal charges are given to two spheres of different radii. The potential will be
An infinite long plate has surface charge density σ . As shown in the figure a point charge q is moved from A to B. Net work done by electric field is:
If n capacitors each of capacitance C are connected in series with a battery of V volt, then electrostatic energy stored in all the capacitors will be
The equivalent capacitance Cs of these series-connected capacitors is
Energy stored in all capacitors
A galvanometer of resistance 100 ohm gives full scale deflection with 0.01 A current. How much resistance in ohm should be connected in parallel to convert it into an ammeter of range 10 A.
Energy obtained when 1 mg mass is completely converted to energy is (in joules)
The material used to slow down neutrons in a reactor is called
The number of photo electrons emitted for light of a frequency v (higher than the threshold frequency v0) is proportional to:
A person cannot see clearly distances more than 40 cm. He advised to use lens of power
In spectral radiancy curve for cavity radiation, the wave-length of the maximum spectral rediancy
If α and β are the collector emitter short circuit current amplification factor and collector base short circuit current amplification factor respectively of a transistor, then α is equal to
Energy required to break one bond in DNA is approximately
With rise in temperature, the specific resistance of semiconductors
In case of a semiconductor which of the following statement is wrong
Which of the following when added as an impurity into the silicon produces n-type semiconductor
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
The light from a sodium vapour lamp passes through a single narrow slit and then through two close, parallel narrow slits. The single slit lies on the perpendicular bisector of the line joining the two close, parallel slits. An observer looking towards the lamp through the double slit will see
Both light and sound waves produce diffraction. It is more difficult to observe the diffraction with light waves because
If a star is moving towards the earth, then the spectrum lines are shifted towards
Conversion of acetaldehyde into ethyl acetate in presence of aluminium ethoxide is called
Reduction of a carbonyl group to a methylene group by alkaline decomposition of the hydrazone is known as
The reagent with which both acetaldehyde and acetone react easily is
An alkane C7H16 is produced by the reaction of Lithium di (3-pentyl) cuperate with ethyl bromide. The structural formula of product is
Which functional group participates in the formation of disulphide bond in proteins?
Hydrolysis of an ester gives a carboxylic acid which on Kolbe's electrolysis yields ethane .The ester is
The reaction of chloroform with alcoholic KOH and p-toludine forms
Hydrolytic reaction of fats by caustic soda is known as
The rate of forward reaction is two times that of the reverse reaction at a given temperature and identical concentration, K equilibrium is
The heat of combustion of yellow and red phosphorus are -9.91 kJ mol-1 and -8.78 kJ mol-1 respectively. The heat of conversion of yellow P → red P is
An ideal gas heat engine operates in Carnot cycle between 227oC and 127oC. It absorbs 6 x 104 cals of heat at higher temp. Amount of heat converted into work is
Which of the following is expected to exhibit optical isomerism?(en=ethylenediamine)
In the following reaction C₆H₆NH₂ + CHCl₃ + 3NaOH → A + 3B + 3C the product A is
When same quantity of electricity is passed through aqueous AgNO3 and H2SO4 solutions connected in series, 5.04 x 10-2 gram of H2 is liberated. What is the mass of silver (in grams) deposited?(Eq. wts. of Hydrogen = 1.008, silver = 108)
What is the electrochemical equivalent (in g coulomb-1) of silver?
(Ag = 108; F = Faraday)
The ether that undergoes electrophilic substitution reaction is
The electrolysis of aqueous NaCl produces at cathode and anode respectively
Electrolytic reduction method is used in the extraction of
The number of NaCl molecules in unit cell of its crystal is
In Nacl, No of Na+ ions = 12 (at edge centres) x 1/4 + 1 (at body centre) x 1 = 3 + 1 = 4
No of Cl- ions = 8 (at corners) x 1/8 + 6 (at face centre) x 1/2 = 1 + 3 = 4
So 4 unis of NaCl
Which of the following will lose optical activity on treatment with diimide H N ═ N H ?
CuSO4 reacts with KCN solution and forms
2CuSO4 + 10KCN → 2K3 [Cu (CN)4] + (CN)2 + 2K2SO4
Fill in the blank with appropriate word.
The firm has enjoyed steady........in the last ten years.
Out of the given alternatives, choose the one which can be substituted for the given capitalised word.
He cannot MAKE BOTH ENDS MEET.
Improve the sentence by choosing best alternative for capitalised part of the sentence.
Every human adance carries with it not only automatic benefits but also a new responsibility, and we must remain constantly AWARE FOR the dangers that lie in the possible misuse of our enormous skills.