Electric Circuits Answers

A proton is accelerated through a potential difference of 100V and the enters a region in which it is moving perpendicular to a magnetic field of flux density 0.20T. Find the radius of the circular path in which it will travel.

a. 0.9km
b. 0.7km
d. 0.3km
d. 0.5km

An electric field of 50kV/m is perpendicular to a magnetic field 0.25T. What is the velocity of a charge whose initial of motion is perpendicular to both fields and which passes through the fields undeflected?

a. 3×10^3m/s
b. 2×10^5m/s
c. 4×10^7m/s
d. 5×10^4m/s

A rectangular coil of dimensions 20cm by 15cm lies with its plane parallel to a magnetic field of 0.5W/m^2. The coil, carrying a current of 10A experiences a torque of 4.5Nm in the field. How many loops has the coil?

a. 100
b. 60
c. 30
d. 20

One end of a simple rectangular wire-loop current balance is inserted into a solenoid. A force of 3.0×10^−3N is found to act on this end when a current of 2.0A is flowing in it. If the length of the conductor forming the end of the the wire-loop is 0.10m. What is the magnetic flux density in the solenoid?

a. 0.043T
b. 0.26T
c. 0.43T
d. 0.015T

A capacitor of 2.0μF is connected to a battery of 2.0V through a resistance of 10kΩ. What is the initial current in the circuit and the current after 0.02s?

a. 0.5μA and 0.074mA
b. 7.4A and 5.0mA
c. 0.2μA and 0.074mA
d. 6.2μA and 7.04mA

A galvanometer with coil resistance 12.0Ω shows full scale deflection for a current of 2.5mA. How would you convert it into a voltmeter of range 0 to 10.0V?

a. 3988Ω in series
b. 0.43Ω in parallel
c. 2000Ω in parallel
d. 1.62Ω in series

A galvanometer of resistance 120Ω a full scale deflection with a current of 0.0005A. How would you convert it to an ammeter that reads a maximum current of 5A?

a. connect 2000Ω in parallel to it
b. connect 200.12Ω in series to it
c. connect 20.10Ω in series to it
d. connect 0.012Ω in parallel to it

A tangent galvanometer has a coil of 2 turn of mean radius 7.5cm, which is set with its plane in the magnetic meridian. A current is passed through the coil and produces a deflection of a magnet, pivoted at the center of the coil, of 450. Calculate the current if the horizontal component of the earth’s flux density is 1.8×10^−5Wbm^−2

a. 1.07A
b. 3.27A
c. 1.33A
d. 2.15A

A charge q1, = 5.0μc is placed 30cm to the west of another charge q2=12μc. What is the force exerted by the positive charge on the negative charge?

a. 24N
b. -6N
c. -8N
d. 4.5N

The term 'lost volts' refers to_________

a. energy per coulomb dissipated in the external (load) resistance
b. terminal potential difference
c. energy per coulomb dissipated in the internal resistance of the source of emf d. energy per coulomb wasted to heat up the connecting wires