Consider the following statements.
An ordinary light bulb has a rather short life because the
1. Filament wire is not uniform.
2. Bulb cannot be evacuated completely.
3. Wires supporting the filament melt at high temperatures.
Which of the above statements are correct?

A. an inverter B. a ups C. a step up transformer D. a step down transformer

A. 40 Ω B. 20 Ω C. 60 Ω D. 800 Ω

A. charge flow B. voltage flow C. water flow D. air flow

A. conduct electricity at lower temperature B. offer high resistance to the flow of current C. offer not resistance to the flow of current D. conduct electricity at high temperature