Figure below shows a plot of current I through the cross-section of a wire over a time interval of 12s. How much charge flows through the wire during this time period?
50 C
To calculate the total charge, we use the formula \( Q = I \times t \), where \( I \) is the current and \( t \) is the time. From the graph, the current increases linearly from 0 to 5 A over the first 4 seconds, so the average current during this interval is 2.5 A. For the remaining 8 seconds, the current stays constant at 5 A.
For the first 4 seconds:
\[ Q_1 = \text{Average current} \times \text{Time} = 2.5 \, \text{A} \times 4 \, \text{s} = 10 \, \text{C} \]
For the next 8 seconds:
\[ Q_2 = \text{Current} \times \text{Time} = 5 \, \text{A} \times 8 \, \text{s} = 40 \, \text{C} \]
Total charge \( Q = Q_1 + Q_2 = 10 \, \text{C} + 40 \, \text{C} = 50 \, \text{C} \)
Important Questions from Current Electricity
Figure shows drift speed Vd of conduction electrons in a copper wire versus position (X) for the three sections. Then,
A. Radius of III > Radius of II > Radius of I
B. Electric Field in III > Electric Field in II > Electric Field in I
C. Radius of wire is same in all sections
D. Conductivity is same in all sections
Choose the correct answer from the options given below:
Which of the following circuits cannot be used to measure the resistance of resistor R?
The temperature at which the resistance of a conductor becomes 30% more than that of its resistance at 47°C will be:
(Given the value of the temperature coefficient of resistance of the conductor is 2 × 10-4 K-1.)
Cell having an emf E and internal resistance r is connected across a variable external resistance R. As the resistance R is increased, the plot of potential difference V across R is given by:
In the potentiometer circuit, the balance point is at X. The balance point will be shifted right towards B when:
A. Resistance R is increased keeping all other parameters constant
B. Resistance S is increased keeping all other parameters constant
C. Cell P is replaced by another cell whose emf is lower than Q
D. The polarity of Q is reversed
Choose the correct answer from the options given below:
