6000V
600V
240V
60V
24V
Correct answer is B
For transformers, \(\frac{V_p}{V_s}\) = \(\frac{N_p}{N_s}\) = \(\frac{I_p}{I_s}\)
\(\frac{500}{2500}\) = \(\frac{120}{V_s}\)
Vs = 600v
Which of the following statements is NOT correct?
A galvanometer can be converted to an ammeter with a different range by connecting a high resistance in series
An electric current always produces a magnetic field
Maxwell's screw rule states that if a corkscrew moves inthe direction of the current, the hand turns in the direction of the lines of force
Electromagnets are used in electric bells and telephone recievers
The lines of force round a straight current carrying conductor are circular
Correct answer is A
No explanation has been provided for this answer.
i only
ii only
iii only
ii and iii only
i,ii and iii
Correct answer is B
No explanation has been provided for this answer.
14.4\(\Omega\)
28.8\(\Omega\)
144\(\Omega\)
288\(\Omega\)
2880\(\Omega\)
Correct answer is B
Heat energy = Electrical energy
6 x 105 = \(\frac{V^2}{R}\)t
R = \(\frac{240 \times 240 \times 5 \times 60}{6 \times 105}\)
= 28.8\(\Omega\)
8 : 1
4 : 1
2 : 1
1 : 1
1 : 4
Correct answer is C
Resistance \(\alpha\) \(\frac{length}{area}\)
\(\frac{R_Q}{R_P}\) = \(\frac{L_QA_P}{L_PA_Q}\)
LQ = 2LP
DQ = 2DP
AP = \(\pi\)\(\frac{(2D_P)^2}{2}\)
= \(\pi\)DP
AQ = \(\pi\)\(\frac{(D_P)^2}{2}\)
= \(\frac{1}{4}\)\(\pi\)DP
therefore, \(\frac{R_Q}{R_P}\) = \(\frac{2L_P \times \pi D_P}{L_P \times \frac{1}{4} \pi D_P}\)
= 2 : 1