In the inductive circuit given in the figure, the current rises after the switch is closed. At instant when the current is 15 mA, then potential difference across the inductor will be
zero
240 V
180 V
60 V
What is the area of the plate of a 3 F parallel plate capacitor, if the separation between the plates is 5 mm?
12.981 x 102 m2
9.281 × 109 m2
1.69 × 1012 m2
4.529 × 109 m2
A magnetising field of 1600 A/m produces a magnetic flux 2.4 x10-5 Wb in an iron bar of cross-sectional area 0.2 cm2. The susceptibility of an iron bar will be
1788
1192
596
298
If the earth field induction at a place is 0.36 gauss and the angle of dip is 60°, the horizontal and vertical components of the field will be respectively
0.18 gauss, 0.18 gauss
0.98 gauss, 0.9 gauss
1.08 gauss, and 1.08 gauss
1.07 gauss, 0.11 gauss
The sun delivers 104 W/m2 of electromagnetic flux to the earth's surface. The total power that is incident on a roof of dimension (10 x 10) m2 will be
104 W
105 W
106 W
107 W
X-rays are not used for radar purposes because they are not
reflected by target
partly absorbed by target
electromagnetic waves
completely absorbed by target
A.
reflected by target
X-rays are not reflected from the tanget, so these cannot be used for radar.
An 8 µF capacitor is connected across 200 V, 50 Hz line. What is the peak value of the charge through capacitor?
2.5 x 10-3 C
2.5 x 10-4 C
5 x 10-5 C
7.5 x 10-2 C
A wire carrying current i and other carrying is in the same direction produce a magnetic field B at the midpoint. What will be the field when 2i current is switched off ?
B/2
2B
B
4B
A drift velocity offree electrons in a conductor is vd, when the current i is flowing in it. If both the radius and current are doubled, the drift velocity will be
Vd