Evaluation Exam 9 Flashcards
A copper wire is drawn down such that its length is doubled but the volume remains the same, what is the new resistance of the wire?
A. R1
B. R1/2
C. 2R1
D. 4R1
4R1
Which statement is true?
A. Magnetic flux lines have sources only
B. Magnetic flux lines have sinks only
C. Magnetic flux lines have both sources and sinks
D. Magnetic flux lines does not have sources and sinks
Magnetic flux lines does not have sources and sinks
Tesla is the unit of
A. magnetic induction
B. self-inductance
C. magnetic flux
D. none of these
magnetic induction
The resistance of resistor 1 is twice of resistor 2. The two are connected in SERIES and a potential difference is maintained across the combination. What is the rate of thermal energy generation in resistor 1?
A. Twice that in resistor 2
B. Four times that in resistor 2
C. Half that in resistor 2
D. The same as that in resistor 2
Twice that in resistor 2
Which of the following protective device operates on the principle of Kirchoff’s Current Law?
A. Instantaneous Overcurrent Relay
B. Undercurrent Relay
C. Differential Protective Relay
D. AC Time Overcurrent Relay
Differential Protective Relay
The magnetic torque exerted on a flat current-carrying loop of wire by a uniform magnetic field B is
A. maximum when the plane of the loop is perpendicular to B
B. independent of the orientation of the loop
C. maximum when the plane of the loop is parallel to B
D. dependent on the shape of the loop for a fixed loop area
maximum when the plane of the loop is parallel to B
A resistor with resistance R1 and a resistor with resistance R2 are connected in parallel to an ideal battery with emf V. What is the rate of thermal energy generation in the resistor with resistance R1?
A. V2/R2
B. V2R1 / (R1 + R2)^2
C. V2/R1
D. V2 / (R1+R2)
V2/R1 or V^2/R1
The units of motional emf are:
A. volt/second
B. volt x meter/second
C. volt/tesla
D. tesla x meter^2/second
tesla x meter^2/second
Ohm’s law is not applicable to
A. dc circuits
B. high currents
C. small resistors
D. semi-conductors
semi-conductors
The study of illumination involves
A. design of lighting system
B. study of lighting and wiring system
C. calculation of wiring sizes for various lighting fixtures
D. study of photometry and its application
design of lighting system
Two wires made of the same material have the same lengths but different diameters. They are connected in parallel to a battery. The quantity that is NOT the same for the wires is:
A. the end-to-end potential difference
B. the current
C. the current density
D. the electric field
the current
What is the unit of relative permeability?
A. Henry
B. Henry/meter
C. henry/meter^2
D. unitless
unitless
An initially uncharged capacitor C is connected in series with the resistor R. This combination is then connected to a battery of emf Vo. Sufficient time elapses so that a steady state is reached. Which of the following statements is NOT true?
A. The final charge on C is independent of R
B. The time constant of independent of Vo
C. The total thermal energy generated by R is independent of R
D. The total thermal energy generated by R is independent of Vo
The total thermal energy generated by R is independent of R
Out of the following select the best conductor of electricity
A. Graphite
B. China clay
C. Porcelain
D. Rubber
Graphite
The voltage applied across an electric press was reduced by 50%. The power consumed by the press will be reduced by?
A. 25%
B. 50%
C. 60%
D. 75%
75%
What is the resistance of an open fuse circuit?
A. At least 1000 ohms
B. Infinity
C. Zero
D. 100 ohms standard temperature
Infinity
