Question E7G11:
What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 3,300 ohms and RF is 47 kilohms?  

Choices:  
A: 28  
B: 14  
C: 7  
D: 0.07    

Correct Answer is  B: 14  

For Figure E7-3 (an inverting op-amp), R1 is the input resistor and RF is the feedback resistor. The inverting amplifier voltage gain is:

$$A_v = -\frac{R_F}{R_1}$$

Since the question asks for absolute voltage gain, use the magnitude:

$$|A_v| = \frac{R_F}{R_1} = \frac{47\,\text{k}\Omega}{3.3\,\text{k}\Omega} \approx 14.24 \approx 14$$

Why 14 is correct:
- The inverting op-amp gain magnitude is the feedback-to-input resistor ratio.
- With 47 kΩ and 3.3 kΩ, the ratio is about 14.24, which rounds to 14.

Why the others are incorrect:
- 28: Not supported by the inverting gain formula; it would imply roughly double the correct ratio. It does not come from either $R_F/R_1$ or $1 + R_F/R_1$.
- 7: About half the correct value; no standard op-amp configuration here yields 7 with these resistors.
- 0.07: This is the reciprocal, $R_1/R_F \approx 3.3/47 \approx 0.07$, which would be a mistake of inverting the ratio.

Useful formulas/rules:
- Inverting op-amp: $$A_v = -\frac{R_F}{R_1}, \quad |A_v| = \frac{R_F}{R_1}$$
- Non-inverting op-amp (for comparison): $$A_v = 1 + \frac{R_F}{R_1}$$
- Units cancel in the ratio; you can use kΩ directly.