DC Circuit Basics - Assignment Example

Question 1. A parallel-plate capacitor holds 10 μC of charge on each plate when connected to a 12 V battery. If you were to slide a dielectric between the plates while the battery maintains the voltage at 12 V, the capacitor would hold a. more than 10 μC of charge b. less than 10 μC of charge c. the same 10 μC of chargeQuestion 2 1. Explain your reasoning for the previous question.  How did you come to choose this answer?The relation linking charge, capacitance and voltage is: Q=CV, where Q is charge, C is Capacitance and V is VoltageIn this case ‘V’ is kept as constant at 12V.

However, due to inclusion of dielectric between the plates, the capacitance of the capacitor has increased. In simple terms, capacitance is defined as the charge storing ability of the capacitor. Therefore, when the capacitance is increased the capacitor would be able to store more than 10microcoloumbs of charge. Mathematically, ‘Q’ is directly proportional to ‘C’ keeping ‘V’ constant. The latter proves the same point. Question 3 1. A battery has a positive side and a negative side.

If you are given a battery and a light bulb in a holder with two contact points, which way or ways of hooking up the battery will light the bulb? a. Either A or B but not C b. C c. A, B, and C would all light the bulb, but C would be brighter d. none would light the bulbQuestion 4 1. Record your reasoning for the previous question.  How did you come to this conclusion?There are two vital components required for electric current to flow:1) Presence of a potential difference, which is the driving force of the current.2) A complete circuit, connecting to the positive and negative end of the voltage source.

In question 3, the diagram has a voltage source and a resistance, in the form of a lamp. In order for the lamp to light a complete circuit in order for the electric current to flow is necessary. The electrons flow from high positive potential to low negative potential (in conventional current) through a low resistance path. In case, the circuit is not complete, the electrons encounter a high resistance path i.e air or vacuum. The latter causes no current to flow leading to the lamp not lighting.

Mathematically, the ohms law provides reason. Ohms law is stated as: V=IR; where V is Voltage, I is Current and R is Resistance.With minor adjustments we have:I=V\RSince, air or vacuum have high resistance we can assume them to be infinite. Taking ‘R’ as infinite, the current reaches a value of zero. The zero value of current would not light the lamp.Question 5 1. You have a toy car that runs on two batteries.  If you could hook it up with only one battery, it would draw a. twice as much current as with two batteries b.

half as much current as with two batteries c. the same current as with two batteriesQuestion 6 1. Explain your reasoning for the previous question.  How did you come to choose this answer?The current drawn from a battery is linked with the potential difference across the battery. When two batteries were attached the potential difference was twice as much as when a single battery was connected. Applying the latter fact with Ohms law: V=IR; where Vis the Voltage, I is Current and R is Resistance.

With minor shifting, we have:I=V\RSince the same toy car is used each time, we can safely assume that ‘R’ is constant. This gives the relation, I is directly proportional with V. When V is halved then I must also be halved. Therefore, option B being correct.Question 7 1. Which will consume more electrical power, a blender that draws 4 amps from a 120 V home outlet or a car vacuum that draws 5 amps from as 12 V car battery? a. the blender b. the vacuum c. they draw the same power d. which one draws more power depends on how long they are runQuestion 8 1.

Explain your reasoning for the previous question.  How did you come to choose this answer?Power is related to current and voltage through the following formula: P=IV; where I is current and V is Voltage.Substituting the values for the blender and car vacuum separately we find that the power drawn for the blender is 480W while power drawn by the car vacuum is 60W. And so, we can conclude that the blender draws more power.