- ATwo extra protons and two extra electrons.
- BTwo extra protons but no extra electron.
- CTwo extra neutrons and no extra electron.
- DTwo extra neutrons and two extra electrons.
Explanation:
12C and 14C are the two isotopes of carbon atom that have same atomic number, but different mass numbers. This means that they have same number of protons and electrons, but different number of neutrons. Therefore, 12C has 6 protons, 6 electrons and 6 neutrons, whereas 14C has 6 electrons, 6 protons and 8 neutrons.
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The alternating voltage induced in the secondary coil of a transformer is mainly due to
|
(a) A varying electric field |
(b) A varying magnetic field |
|
(c) The vibrations of the primary coil |
(d) The iron core of the transformer |
Assertion : In everyday life the Doppler’s effect is observed readily for sound waves than light waves.
Reason : Velocity of light is greater than that of sound.
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |
Coating of strontium oxide on Tungsten cathode in a valve is good for thermionic emission because
|
(a) Work function decreases |
|
(b) Work function increases |
|
(c) Conductivity of cathode increases |
|
(d) Cathode can be heated to high temperature |
If a slab of insulating material 4
thick is introduced between the plates of a parallel plate capacitor, the separation between plates has to be increased by 3.5
to restore the capacity to original value. The dielectric constant of the material will be
|
(a) 6 |
(b) 8 |
(c) 10 |
(d) 12 |
Dielectric constant of pure water is 81. Its permittivity will be
|
(a) |
(b) 8.86 |
|
(c) 1.02 |
(d) Cannot be calculated |
50 Ω and 100 Ω resistors are connected in series. This connection is connected with a battery of 2.4 volts. When a voltmeter of 100 Ω resistance is connected across 100 Ω resistor, then the reading of the voltmeter will be
|
(a) 1.6 V |
(b) 1.0 V |
(c) 1.2 V |
(d) 2.0 V |
The equivalent quantity of mass in electricity is
|
(a) Charge |
(b) Potential |
(c) Inductance |
(d) Current |