Ch 3. Current Electricity Flashcards
The relation between the drift velocity (V d) and applied electric field (E) of a conductor is
V d ∝ E
V d Proportional To E
Two resistors R and 2R are connected in series in an electric circuit. The thermal energy developed in R and 2R will be in ratio
1:2
The motion of electron inside the conductor is
Drifting
What is mainly measured by potentiometer?
Potential Difference
One ampere is equal to
1 coulomb/1 second
Unit of electromotive force is
Volt
Which of the following is correct for resistivity of a material?
P = RA/L
The heat produced in a conductor of resistance R due to flow of current I for time t is
I².R.t
Value of green colour code on carbon resistance is
5
The value of yellow colour in colour code of carbon resistance is
4
Which of the following is the best conductor of electricity?
Silver
Which of the following is the same in parallel connection of resistances?
Potential difference
1 volt is equal to
1JC⁻¹
The value of red colour in colour code of carbon resistance is
2
At constant potential difference, the resistance of any electric circuit is halved, the value of heat produced will be
Double
The current flowing in a wire is 1A. If the charge of an electron is 1.6 × 10¹⁹C, then the number of electrons flowing through the wire per second is
6.25 × 10¹⁸
When two bulbs of power 60W and 40W are connected in series, then the power of their combination will be
24W
The specific resistance of a conductor increases with
Increase of temperature
The drift velocity (Vd) and applied electric field (E) of a conductor are related as :
Vd ∝ E
Two cells of e.m.f. ε₁ and ε₂, internal resistance r₁ and r₂, connected in parallel. The equivalent e.m.f. of the combination is
ε₁ r₂ + ε₂ r₁/ r₁ + r₂
Which element is used in electric heater?
Nichrome
Absorbed electrical energy is
Proportional to the square of the potential difference
Dimension of electromotive force (e.m.f.) is
M¹ L² T⁻³ I⁻¹
Ampere - hour is unit of
Charge
The power of electric circuit is
V²/R
A current flows in a wire of resistance 5Ω having potential difference 7 volt for 20 minutes. The heat produced is
2800 cal
In the following Question Nos. (1) to (4), there are two columns. Column 1 contains 4 questions. You have to match the correct options of these questions as A, B,C,D from column 2.
Ohm’s law — Potential difference/current = Constant
Kirchhoff’s law — Conservation of energy
Force × Velocity — Potential difference × current
Kilowatt-hour — Potential difference × current × Time
A current of 10 ampere flows in a wire for 10 second. If potential difference across the wire is 15 Volt, the work done will be
1500J
The electrical resistance of a healthy man is
50,000Ω
Kilowatt-hour (kWh) is the unit of
Energy
Statement 1 : The electrical lamp light up immediately after switch is on.
Statement 2 : The free electrons of fire move with speed of light.
Statement 1st is true, but Statement 2nd is false.
Statement 1 : A large dry cell has higher e.m.f.
Statment 2 : The e.m.f of a dry cell is proportional to its size.
Statement 1st is false, but Statement 2nd is true.
Which of the following is correct for current density?
J = I/A
Which of the following is correct for mobility?
µ = Vd/E
Which of the following is correct?
1 watt = 1 Js⁻¹
Colour code of carbon resistance for blue colour is
6
Wheatstone’s bridge is used in measuring
Both high and low resistance
The algebraic sum of all currents meeting at any point in an electrical circuit is
Zero
