11.
Which of the following is a device designed to protect electrical devices from voltage spikes?

12.
The working of the quartz crystal in the watch is based on the

13.
At low temperature, Lead behaves as a :

14.
The device which transfer the signal from low resistance region to high resistance region is

15.
The frequency of direct current is ________

16.
Resistance of human body in dry condition

17.
The purpose of choke in a fluorescent lamp is :

18.
An electron and a proton starting from rest get accelerated through potential difference of 100 kV. The final speed of the electron and the proton are Ve and Vp respectively. Which of the following relations is correct?

19.
Superconductors are those elements

20.
A device used for converting a.c. into d.c. is called