Electricity Tes...

A block of carbon, $$1.0 cm$$ by $$2.0 cm$$ by $$5.0 cm$$, has a resistance of $$0.015 \ \Omega$$  between its two smaller faces. What is the resistivity of carbon?

 A wire of uniform cross-section has a resistance of $$R$$ . If it is drawn to three times the length, but the volume remains constant, what will be its resistance?

Human body is a 

What length of German silver wire, diameter $$0.050 cm$$, is needed to make a $$28 \Omega$$  resistor, if the resistivity of German silver is $$2.2 \times  10^{-7} \Omega  m$$?

A wire of uniform cross-section has a resistance of $$R \ \ \Omega$$. What would be the resistance of a similar wire, made of the same material, but twice as long and of twice the diameter?

Four bulbs marked $$40W, \ 250V$$ are connected in series with $$250\ V$$ mains, the total power consumed is

What is the minimum number of bulbs, each marked $$60W, \ 40V,$$ that can work safely when connected in series with a $$240V$$ mains supply?

Two wire of same metal have same length but their cross-sections are in the ratio $$3:1$$. They are joined in series. The resistance of thick wire is $$10$$. The total resistance of combination will be

A $$100W, 200V$$ bulb is connected to a $$160V$$ supply. The actual power consumption would be

$$1$$ kilowatt hr $$=$$ __________ joules.