Physics - Study Mode

[#186] Super conductors are substances that
Correct Answer

(A) Offer minimum resistance to flow of electric current

Explanation

Solution: Superconductors are substances which display zero electrical resistance when a current is supplied, and are able to propagate such a current in a circuit indefinitely.

[#187] A galvanometer can be converted to a voltmeter by connecting
Correct Answer

(B) A high resistance in series

Explanation

Solution: A galvanometer is converted into a voltmeter by connecting with high resistance.

[#188] Certain substances loose their electrical resistance completely at super low temperature. Such substances are called.
Correct Answer

(A) Superconductors

Explanation

Solution: The substances which lose their resistance completely at very low temperature are called Superconductors.

[#189] The potential difference between the terminals of an electric heater is 60 V when it draws a current of 4 A from the source. What current will the heater draw if the potential difference is increased to 127.5 V ?
Correct Answer

(A) 8.5 A

Explanation

Solution: V = 60V and I = 4A R = V/I u200b= 60/4 u200b=15Ω When potential difference is increased to 127.5 V I = V/R u200b= 127.5/15 u200b= 8.5 A The current through the heater becomes 8.5 A.

[#190] Which of the following experiments analyzed the Fraunhofer lines of the solar spectrum?
Correct Answer

(D) Bunsen and Kirchhoff's experiment

Explanation

Solution: Bunsen and Kirchhoff's experiment analyzed the Fraunhofer lines of the solar spectrum.