PHY102: General Physics 11 ASSIGNMENT TO BE SUBMITTED ON THE EXAM DAY

The electromotive force (e.m.f.) of a cell is the potential difference across its terminals when no current is flowing through the external circuit (i.e., when the circuit is open). This is the maximum potential difference the cell can provide.

The correct option is (B).
The potential difference between the terminals of a cell when the cell is not delivering current to a circuit is referred to as $\boxed{\text{B) electromotive force}}$.

For a sinusoidal alternating current, the root mean square (RMS) value ($I_{rms}$) is related to the peak value ($I_{peak}$) by the formula:

Given $I_{peak} = 5 \text{ A}$:

Rounding to two decimal places, $I_{rms} = 3.54 \text{ A}$.

The correct option is (A) or (C), as they are identical.
The r.m.s. value of an a.c. whose peak value is 5 A is $\boxed{\text{A) } 3.54 \text{ A}}$.

When cells are connected in series, their individual electromotive forces (e.m.f.s) add up to give the total effective e.m.f. of the combination.

Given three cells, each with an e.m.f. of $3.54 \text{ V}$:

The correct option is (B).
The effective e.m.f. is $\boxed{\text{B) } 10.62 \text{ V}}$.

The capacitive reactance ($X_C$) of a capacitor is given by:

where $f$ is the frequency and $C$ is the capacitance.

Given $X_C = 500 \Omega$ and $C = 20 \text{ µF} = 20 \times 10^{-6} \text{ F}$:

The correct option is (B).
The frequency at which a 20 µF capacitor will have a reactance of 500 Ω is $\boxed{\text{B) } \frac{50}{\pi} \text{ Hz}}$.

The magnetic force exerted by a magnet is strongest at its ends. These regions are called the poles of the magnet.

The correct option is (C).
The ends of a magnet where its attracting power is greatest are called $\boxed{\text{C) poles}}$.

Ohm's Law relates potential difference ($V$), current ($I$), and resistance ($R$) as:

Given $I = 8 \text{ A}$ and $R = 4 \Omega$:

The correct option is (C).
The potential difference across the terminals of the conductors is $\boxed{\text{C) } 32 \text{ V}}$.

The capacitance ($C$) of a capacitor is defined as the ratio of the charge ($Q$) stored on it to the potential difference ($V$) across its plates:

Given $Q = 2.5 \times 10^{-3} \text{ C}$ and $V = 320 \text{ V}$:

Since $1 \text{ µF} = 10^{-6} \text{ F}$:

Rounding to one decimal place, $C = 7.8 \text{ µF}$.

The correct option is (A).
The capacitance of the capacitor is $\boxed{\text{A) } 7.8 \text{ µF}}$.

The general equation for an alternating voltage is:

where $V_{peak}$ is the peak voltage and $\omega$ is the angular velocity.

Given the relation $V = 4 \sin(900t)$, by comparing it to the general form, we can see that:

The correct option is (D).
The angular velocity of the voltage is $\boxed{\text{D) } 900 \text{ rad s}^{-1}}$.

The process of a magnet losing its magnetic properties is known as demagnetization.

The correct option is (A).
The process by which a magnet loses its magnetism is known as $\boxed{\text{A) demagnetization}}$.

The resistance ($R$) of a wire is given by:

where $\rho$ is the resistivity, $L$ is the length, and $A$ is the cross-sectional area.

Given diameter $D = 0.07 \text{ cm} = 0.07 \times 10^{-2} \text{ m}$.
The radius is $r = D/2 = 0.035 \times 10^{-2} \text{ m}$.
The cross-sectional area of a circular wire is $A = \pi r^2$:

Given $R = 10 \Omega$ and $L = 55 \text{ cm} = 0.55 \text{ m}$:

Rounding to one significant figure, $\rho = 7.0 \times 10^{-6} \Omega \text{m}$.

The correct option is (D).
The resistivity of the material is $\boxed{\text{D) } 7.0 \times 10^{-6} \Omega \text{m}}$.

The total electrical energy ($E$) consumed by an appliance is given by:

where $V$ is the voltage, $I$ is the current, and $t$ is the time.

Given $V = 220 \text{ V}$, $I = 2.5 \text{ A}$, and $t = 400 \text{ s}$:

Since $1 \text{ KJ} = 1000 \text{ J}$:

The correct option is (D).
The total energy consumed by the cooker is $\boxed{\text{D) } 220 \text{ KJ}}$.

A variable resistor used to control current in a circuit is called a rheostat.

The correct option is (D).
A variable resistor which is used to adjust the current flowing in a circuit is called a $\boxed{\text{D) rheostat}}$.

The process of making a magnetic material magnetic by bringing a magnet near it is called magnetic induction, or inducing magnetism.

The correct option is (B).
$\boxed{\text{B) Inducing magnetism}}$ is the process of magnetizing an object made of magnetic material simply by bringing a magnetic near.

The resonant frequency ($f_0$) of a series LC circuit is given by:

where $L$ is the inductance and $C$ is the capacitance.

Given $L = 500 \text{ µH} = 500 \times 10^{-6} \text{ H}$ and $C = 50 \text{ µF} = 50 \times 10^{-6} \text{ F}$. Use $\pi = 3.142$.

Rounding to the nearest whole number, $f_0 = 1007 \text{ Hz}$. The closest option is (A).

The correct option is (A).
The frequency at which the circuit will resonate is $\boxed{\text{A) } 1006 \text{ Hz}}$.

For resistors connected in parallel, the reciprocal of the equivalent resistance ($R_{eq}$) is the sum of the reciprocals of the individual resistances:

Given $R_1 = 1 \Omega$, $R_2 = 5 \Omega$, $R_3 = 3 \Omega$, and $R_4 = 4 \Omega$:

Rounding to two decimal places, $R_{eq} = 0.56 \Omega$.

The correct option is (A).
The value of the net resistance is $\boxed{\text{A) } 0.56 \Omega}$.

For resistors connected in parallel, the reciprocal of the equivalent resistance ($R_{eq}$) is the sum of the reciprocals of the individual resistances:

Given $R_1 = 2 \Omega$, $R_2 = 5 \Omega$, and $R_3 = 10 \Omega$:

The calculated equivalent resistance is $1.25 \Omega$. None of the options (A) $0.59 \Omega$, (B) $0.48 \Omega$, (C) $0.33 \Omega$, (D) $0.27 \Omega$ match this value. There might be an error in the options provided.

Based on the calculation, the resistance in the circuit is $\boxed{1.25 \Omega}$.
Note: This calculated value does not match any of the given multiple-choice options, indicating a potential error in the question's parameters or the options themselves.

The power ($P$) dissipated by a resistor is related to the voltage ($V$) across it and its resistance ($R$) by the formula:

Given $P = 60 \text{ W}$ and $R = 735 \Omega$:

The correct option is (A).
The main voltage for which the lamp is best suited is $\boxed{\text{A) } 210 \text{ V}}$.

Charge per unit area of a surface is known as surface charge density.

The options are missing, but the definition is:
Charge per unit area of a surface is known as $\boxed{\text{surface charge density}}$.