# Multiple Choice Questions on Electric Current

- One coulomb of electrical charge is contributed by how many electrons?Electrical charge of one electron is - 1.6 × 10
^{ - 19}coulomb, hence one coulomb implies 1 / | - 1.6 × 10^{ - 19}| or 0.625 × 10^{19}number of electrons. - 5 × 10
^{16}electrons pass across the section of a conductor in 1 minutes and 20 seconds. The current is flowingThe charge of an electron is - 1.6 × 10^{-19}coulomb. Therefore total negative charge passes across the section of a conductor in 1 minute and 20 seconds is 5 × 10^{16}× 1.6 × 10^{-19}= 8 × 10^{ - 3}. Therefore, charge passes across the section in one second, is 8 × 10^{ - 3}coulomb / 80 second = 10^{ - 4 }coulomb/second (or Amp) = 0.1 mA. - An current of 6 A is same asCurrent is the rate of charge transferred per second. A current of 6 ampere implies 6 coulomb charge transferred through a cross section of conductor per second. Therefore 6 ampere = 6 coulomb / second.
- Ampere - second is the unit ofElectric current is nothing but rate of flow of charge per second. Therefore, ampere = coulomb / second. Hence coulomb = ampere × second = ampere - second.
- The current in a circuit follows the relation i = 100sinωt. If frequency is 25 Hz, how long will it take for the current to rise to 50 A ?Let, at t second the instantaneous value of current, i = 50 A.
- The equation of a current is given by i = I
_{m}sin2ωt. The frequency of the current in Hz is - The equation of alternating current is i = 42.4sin628t. Then the average value of current isThe relation between average value and peak value of a sinusoidal waveform is given by
Here, I _{m}= 42.4 A. Therefore, I_{0}= 0.636 × 42.4 = 26.97 A. - If 1 A current is flowing through a series circuit having 100 resistors of each having resistance of 1 Ω. What will be the current in the circuit where, these 100 resistors are connected in parallel?
- In the figure shown, what will be the current passing through 2 Ω resistor ?
According to current division law, required current,
- A copper conductor of one square millimeter can safely carry an current of
- For carrying an current of 75 A an aluminium conductor should have a minimum cross-section ofThe current carrying capacity of aluminium conductor is near about 3 A / mm
^{2}. - A copper wire of length l and diameter d has potential difference V applied across its two ends. The drift velocity is V
_{d}. If the diameter of the wire is made d / 2, then the drift velocity becomesThe drift velocity is a basic property of conductor material and hence it does not depend upon the length or diameter of the conductor. - Mass of a proton is how many times greater than mass of an electron?Mass of a proton is 1840 times greater than mass of an electron.
- On which factors does the severity of electric shock depends ?The severity and effects of an electrical shock depends on a number of factors, such as the pathway through the body, the amount of current, the length of time of the exposure, whether the skin is wet or dry, magnitude of voltage, and type of supply AC or DC.
- Five coulomb of electrical charge is contributed by how many electrons?Electrical charge of one electron is - 1.6 × 10
^{ - 19}, hence five coulomb implies 5 / | - 1.6 × 10^{ - 19}| or 3.125 × 10^{19}numbers of electrons. - The transient current in a series AC circuit is given by
Find the initial current ? - Alternating current is found most suitable for
- The rms value of a half wave rectified symmetrical square wave current of 2 A is given by
- How many coulombs of charge flows through a circuit carrying 5 A in 5 min?