Grade 12Electric Current

An electrical circuit is shown in the figure. Show that the p.d across the resistor of 400 ohmas will be measured by the voltmeter V of resistance 400 ohm is 20/3 V.

Tushar Watts

16 Years agoGrade 12

1 Answer

Ramesh V

16 Years ago

since voltmeter resisitance is 400 ohms

R_ab= 400*400/800 = 200 ohms , R_ad = 100 , R_cd= 100 ,R_bc =200 and R_ac =100 ohms

as R_ab/R_bc = R_ad/R_cd , by wheat stone bridge priciple, no current flows through Rac, so it can be removed from circuit

now, to fin volatge across, V , let I be current in circuit,

the on simplyfying resistance R_bd = 150 ohms

hence, I = 1/15 A

current in voltmeter = I/2 = 1/30 A

voltage across it = 1/30 * 200 = 20/3 V

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Ramesh
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