A 1000 Ω resistor is in a circuit with 30.0 mA flowing through it. A voltmeter with internal resistance 1000 Ω is used to measure the voltage across the resistor. What is the reading from the voltmeter if 30.0 mA still flows in the circuit?
30.0 V
15.0 V
3.00 V
27.0 V
29.9 V

Question

A 1000 Ω resistor is in a circuit with 30.0 mA flowing through it. A voltmeter with internal resistance 1000 Ω is used to measure the voltage across the resistor. What is the reading from the voltmeter if 30.0 mA still flows in the circuit?
	30.0 V
	15.0 V
	3.00 V
	27.0 V
	29.9 V

anonymous · Answer

The answer is 15.0V 
The explanation is as follows.

Since the voltmeter is attached across the resistor, the arrangement is parallel. 
In a Parallel arrangement, The combined resistance is now  500ohms. 

Again, using V=IR
V=(0.03)(500)
V=15V--------------------------*Answer
In a parallel arrangement, the voltage supplied remains constant to all units.

anonymous · Answer

are u sure ?

anonymous · Answer

I'm pretty positive. Would anyone mind backing up my reply?

anonymous · Answer

Attempt it yourself and compare answers. Use the formula V=IR, and assess the information as the only thing being changed here is the resistance. Apply that change to find out the effect it has on the voltage.

anonymous · Answer

pls @Areesha. ID how do you get the combined resistance to be 500ohms

anonymous · Answer

Alright, firstly voltmeters are always attached in a parallel arrangement so the combined rsistance of both would not simply be added. 
The formula for total resistance of resistors attached in a parallel arrangement is as follows:
1/RT= 1/R1 + 1/R2 + 1/R3 etc..