A total resistance of 3 ohms is to be producd by combining an unknown resistor R with a 12 ohm resistor. What is the value of R and how is it connected to the 12 ohm resistor
a) 4.0 ohm parallel
b) 4.0 ohm in series
c) 2.4 ohm in parallel
d) 2.4 in series
e) 9.0 in parallel

My work: A, 1/12 + 1/4= 1/3 or 3 ohm resistance

By using only two resistors, R1 and R2, a student is able to obtain resistance of 3 ohm, 4 ohm, 12 ohm, and 16 ohm using the alone combination. The values of R1 and R2 (in ohms) are:
A) 3,4
b) 2,12
c) 3, 16
d) 4, 12
e) 4, 16

My answer is d 4,12. Since 4 is alone, 12 is alone. in series 12+4=16 and in parallel the value is 3.

thank you

correct.

1. 👍 1
2. 👎 0
3. 👁 1,346
1. 12*R/(12+R) = 3
3R + 36 = 12R.
9R = 36.
R = 4 Ohms in parallel.

4, and 12 Ohms.

1. 👍 1
2. 👎 0
2. THE ANSWER IS B, 4OHMS PARALLEL

1. 👍 0
2. 👎 0
3. D,4 ohm, series

1. 👍 0
2. 👎 0

## Similar Questions

1. ### Engineering Science (Physics)

A platinum coil has a resistance of 3.146(ohms) at 40'C and 3.767(ohms) at 100'C. Find the resistance and the temperature coefficient of resistance at 0'C. Thanks in anticipation

asked by Xyler on March 14, 2012
2. ### physics

if one resistor is removed from a parallel circuit, the total current will 1) decrease b) increase c) remain the same and the current flowing through each of the remaining branches ____________________. removing one resistor makes

asked by Sejul on May 18, 2011
3. ### physics (thxs again)

Thank you for the help :) A certain sample carries a current of 4A when the potential difference is 2V and a current of 10A when the potential difference is 4V. This samples is: a) obeys ohm's law b) has a resistance of 0.5 ohms

asked by susan on March 14, 2007
4. ### Physics

Three resistors (14.4 Ω, 21.7 Ω, 14.1 Ω) are connected in parallel across 98 V. What is the total resistance for this circuit? What is the voltage drop across the 21.7 Ω resistor? What current is flowing in the 14.1 Ω

asked by Joan on March 13, 2011
5. ### Physics EM

An ammeter is connected in series to a battery of voltage V_b and a resistor of unknown resistance R_u The ammeter reads a current I_0. Next, a resistor of unknown resistance R_r is connected in series to the ammeter, and the

asked by Spencer on March 6, 2008
1. ### science

There are three sources of resistance in a parallel circuit. Two of them are rated at 20 ohms, the other at 10 ohms. What is the circuits total resistance?

asked by teresa on July 5, 2010
2. ### physics

We are given an input current Iin=100μA and a linear resistive load represented by the resistor RL . Our resistive load is not regulated for the high current provided by our current source, so we add a resistor RS in parallel to

asked by Amit on September 14, 2014
3. ### Science

3 resistors having the same resistance value are wired in parallel, how does the equivalent resistance compare to the resistance value of a single resistor? 1) The equivalent resistance is thrice the value of a single resistor. 2)

asked by Skylar on August 3, 2014
4. ### Physics

The constant resistance of a resistor is 30 ohms, independent of the temperature. The resistor is made up of an aluminium resistor with resistance R1 at 0°C in series with a carbon resistor with resistance R2 at 0°C. Evaluate R1

asked by Joseph on October 8, 2017
5. ### Physics

Three resistors having the same resistance value are wired in parallel. How does the equivalent resistance compare to the resistance value of a single resistor? The equivalent resistance is thrice the value of a single resistor.

asked by BoBo on October 22, 2012