1. Kirchhoff's laws are useful in determining:
Verification Matrix:
Kirchhoff's Current Law (KCL) and Kirchhoff's Voltage Law (KVL) form simultaneous linear algebraic networks. While KVL deals with potential loops, the primary, ultimate procedural objective when executing standard Kirchhoff network reduction analysis is solving for the unknown **current branching pathways** flowing through complex circuit legs. Depending on textbook phrasing, a comprehensive response includes options (a) and (b), but option **(a)** is traditionally treated as the direct operational target variable.
2. The resistance of a superconductor is:
Verification Matrix:
When cooled below a specific critical threshold temperature ($T_c$), a superconductor exhibits a quantum state transition where its electrical direct-current ohmic resistance drops to **exactly zero**. Current can circulate indefinitely inside a closed superconducting ring without experiencing active energy dissipation.
3. Reciprocal of resistance is called:
Verification Matrix:
Conductance ($G$) mathematically measures how easily charge carrier populations navigate a structural element. It is defined as the absolute inverse of electrical resistance: $G = \frac{1}{R}$. Its derived SI unit of measurement is the Siemens ($\text{S}$) or mho ($\Omega^{-1}$).
4. The graphical representation of Ohm's law is:
Verification Matrix:
Ohm's law establishes a linear mathematical proportional function: $V = IR$. Plotting Voltage ($V$) versus Current ($I$) for an ohmic material yields a **straight line** passing directly through the spatial origin $(0,0)$, where the constant slope represents the component's internal resistance ($R$).
5. A potential difference is applied across the ends of a wire. If the potential difference is doubled, then the drift velocity of free electrons will:
Verification Matrix:
The average drift speed expressions are governed by field strength: $v_d = \frac{eE\tau}{m} = \frac{eV\tau}{mL}$. This indicates drift velocity maps a direct, first-order proportional relationship to potential difference ($v_d \propto V$). Doubling the voltage factor ($2V$) systematically forces the drift velocity metric to **double** as well.
6. Internal resistance is the resistance offered by:
Verification Matrix:
Internal resistance ($r$) represents the intrinsic structural resistance to charge transport localized directly inside a **source of electromotive force (emf)**, such as the chemicals or electrolytes inside a battery block. It accounts for why terminal voltage drops when real power cells supply active load circuits.
7. Power dissipation in a resistor can't be calculated using which formula?
Verification Matrix:
Combining Joule's Law and Ohm's relation establishes valid algebraic electric power formulas: $P = VI$, $P = I^2R$, and $P = \frac{V^2}{R}$. The expression **$P = \frac{R}{VI}$** is structurally incorrect and yields physically invalid dimensional units.
8. What is a potentiometer primarily used for?
Verification Matrix:
A potentiometer acts as a continuous voltage divider network used for the high-precision **measurement of potential differences (voltage)** or comparing cell emfs without drawing any active baseline current at its balance null point. This null-method design makes it superior to standard non-ideal analog voltmeters.
9. A heat-sensitive device whose resistivity changes with the change in temperature is called:
Verification Matrix:
A **thermistor** (derived from thermal-resistor) is a solid-state semiconductor element meticulously engineered to exhibit large, highly sensitive changes in internal electrical resistance matching minute changes in localized temperature fields. Most feature a Negative Temperature Coefficient (NTC).
10. A wire of uniform area of cross-section A, length L, and resistance R is cut into two parts. The resistivity of each part:
Verification Matrix:
While geometric resistance follows structural measurements ($R = \rho \frac{L}{A}$), electrical **resistivity ($\rho$)** represents an intrinsic material property. It depends solely on the chemical composition and electronic band structure of the material (e.g., copper, iron) along with its temperature field. Subdividing the body length physically changes $R$, but **leaves the local resistivity metric completely unchanged**.
No comments:
Post a Comment