A series circuit contains a generator, two devices, and connecting wires. The resistances of the two devices are 15 ohms and 10 ohms. The voltage supplied by the generator is 75 V. What will be the voltage drop in the device with 10 ohms of resistance? A. 45 V B. 25 V C. 30 V D. 3 V 8. Which of the following is true about semi-conductors: A. Gold and silver are important semiconductors B. Neither free electrons nor holes are considered charge carriers in a semi-conductor C. A material is classified as a semiconductor if its resistance to the flow of electric current is too low to permit it to be called a conductor D. Exposing a crystal of a semiconductor to heat or light starts displacing valence electrons which then move throughout the crystal 15. Imagine that an uncharged pith ball is brought into the electrostatic field of a charged rod. The side of the pith ball closest to the negatively charged end of the rod will A. be given a negative charge produced by the movement of electrons from the other end of the ball. B. not experience any induced charge and remain neutral. C. be given a negative charge produced by the movement of electrons from the rod. D. be given a positive charge produced by the movement of electrons to the other end of the ball. 16. Which of the following is true in regard to a charged atom? A. The magnitude of the negative charge is equal to the magnitude of the positive charge. B. The number of protons and the number of electrons within the same atom are unequal. C. When an atom gains an electron, it becomes a cation, which is positively charged. D. When an atom loses an electron, it becomes an anion, which is negatively charged. 17. Within an integrated circuit, each wafer is cut into sections, which A. carry a single circuit and are placed in individual cases. B. carry a single circuit and are placed all together in one case. C. have multiple circuits and are placed all together in one case. D. have multiple circuits and are placed in individual cases.
The Correct Answer and Explanation is:
1. Voltage Drop in the 10-ohm Device
Total Resistance = 15 ohms + 10 ohms = 25 ohms
Voltage Supplied = 75 V
Using Ohm’s Law:
Current, I = V / R = 75 V / 25 ohms = 3 A
Voltage Drop across the 10-ohm device:
V = I × R = 3 A × 10 ohms = 30 V
Correct Answer:
C. 30 V
Explanation:
In a series circuit, the same current flows through all components. To find the voltage drop across a specific resistor, multiply the current by its resistance. The total current is calculated using the total resistance and supplied voltage. For the 10-ohm device, the voltage drop is 30 volts.
2. True Statement About Semiconductors
Correct Answer:
D. Exposing a crystal of a semiconductor to heat or light starts displacing valence electrons which then move throughout the crystal
Explanation:
Semiconductors like silicon and germanium have electrical properties between conductors and insulators. When exposed to heat or light, their electrons gain energy, break free from atoms, and become mobile charge carriers. Gold and silver are excellent conductors, not semiconductors. In semiconductors, both electrons and “holes” (positive charge carriers) participate in conduction.
3. Behavior of a Pith Ball Near a Negatively Charged Rod
Correct Answer:
D. Be given a positive charge produced by the movement of electrons to the other end of the ball
Explanation:
When an uncharged pith ball enters the field of a negatively charged rod, electrons within the ball are repelled to the far side. This leaves the near side positively charged by induction, though the ball remains overall neutral. The side closest to the rod becomes positively charged due to this redistribution of charges.
4. True Statement About a Charged Atom
Correct Answer:
B. The number of protons and the number of electrons within the same atom are unequal
Explanation:
A neutral atom has equal numbers of protons (positive) and electrons (negative). When the numbers differ, the atom becomes charged, known as an ion. If it gains electrons, it becomes negatively charged (anion). If it loses electrons, it becomes positively charged (cation).
5. Integrated Circuit Sections
Correct Answer:
A. Carry a single circuit and are placed in individual cases
Explanation:
An integrated circuit (IC) is produced on a wafer of semiconductor material. After manufacturing, the wafer is cut into small sections called dies. Each die contains one complete circuit. These are then packaged individually for use in electronic devices. This process allows for mass production of identical circuits efficiently.
