19 Questions
What is the correct definition of current?
The rate of charge flow in a circuit
According to Ohm's Law, what happens to voltage when resistance increases?
Voltage decreases
What is the unit of electric power?
Watts
In terms of electric power calculations, what does P = I^2R represent?
Relationship between current and power
How is charge (Q) calculated when involving current flow and time?
$Q = It$
What is the relationship between charge and number of electrons?
Direct relationship
What is the voltage mentioned in the text?
$125$ volts
What is the electrical resistance of the resistor?
$5$ kilo ohms
How much charge flows through the resistor?
$12.5$ coulombs
What is the correct formula for calculating electric power in a circuit?
P = V/I
If the current flowing through a circuit is 3 amps, what is the rate of charge flow in coulombs per second?
3 C/s
In a circuit with a resistance of 50 ohms and a current of 2 amps, what is the voltage across the circuit?
100 V
How does an increase in resistance affect the current in a circuit?
Decrease in current
What happens to electric power if both the voltage and current in a circuit are doubled?
Power is doubled
If a circuit has a power of 120 watts and a current of 5 amps, what is the voltage across the circuit?
25 V
How does an increase in current affect the power dissipated by a resistor?
Power decreases
What happens to the power dissipated by a resistor if its electrical resistance doubles?
$1/4$ P
In an electric circuit, if the power delivered by the battery is 100 W, what should be the power dissipated by the resistor for energy balance?
$100$ W
What would be the new voltage across a resistor if the charge flowing through it becomes $25$ coulombs and current remains constant at $5$ amps?
$125$ V
Study Notes
- Conventional current states that current flows from the positive terminal to the negative terminal, while in reality, electrons flow from the negative terminal to the positive terminal.
- Current is defined as the rate of charge flow, calculated as charge divided by time (I = ΔQ/Δt) where Q is the electric charge measured in coulombs and t is the time in seconds. The unit for current is amperes (amps), where 1 amp = 1 coulomb per second.
- Ohm's Law describes the relationship between voltage (V), current (I), and resistance (R): V = IR. Resistance is measured in ohms, and increasing current leads to an increase in voltage, while increasing resistance leads to a decrease in current.
- Electric power is the product of voltage and current (P = VI), measured in watts. It can also be calculated as I^2R or V^2/R.
- In a circuit, power delivered by the battery must equal the power dissipated by the resistor for energy balance.
- In a problem involving current flow and time, electric charge (Q) can be calculated as Q = It, where I is the current and t is the time. Conversion of units may be necessary for accurate calculations.
- The relationship between charge and number of electrons is proportional; one electron has a charge of 1.6 x 10^-19 coulombs.- The voltage in part a is 125 volts.
- The internal resistance of the motor is 312.5 ohms.
- The charge flowing through the resistor is 12.5 coulombs.
- The electrical resistance of the resistor is 5 kilo ohms.
- The electric current flowing through the resistor is 0.026 amps or 26 milliamps.
- The power consumed by the resistor is 3.38 watts.
- The voltage across the resistor is 130 volts.
Test your knowledge on electricity and circuits with questions on conventional current flow, Ohm's Law, electric power, charge calculations, and electrical calculations involving voltage, current, and resistance.
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