CBSE
Multiple Choice QuestionsA voltmeter of resistance 998 is connected across a cell of emf 2V and internal resistance 2. The potential difference across the voltmeter is
1.99 V
3.5 V
5 V
6 V
A potential difference V is applied at the ends of a copper wire of length l and diameter d. On doubling only d, drift velocity
becomes two times
becomes half
does not change
becomes one-fourth
The length of a wire of a potentiometer is 100 cm, and the emf of its stand and cell is E volt. It is employed to measure the emf of a battery whose internal resistance is 0.52 Ω.1fthe balance point is obtained at l= 30 cm from the positive end, the emf of the battery is
The material of wire of potentiometer is made of
copper
steel
manganin
aluminium
The electrical resistivity of a sample
is proportional to its length
is proportional to the area of cross-section
is inversely proportional to the length
neither depends on the length nor on the area of cross-section
An ammeter reads upto 1 A. Its internal resistance is 0.81 Ω. To increase the range to 10 A, the value of the required shunt is
0.03 Ω
0.3 Ω
0.9 Ω
0.09 Ω
A small current carrying loop acts as a small magnet. The area of the loop is A and magnetic moment is M. The current in the loop will be
MA
A2M
Temperature of a piece of silicon is raised from 27°C to 100°C, then its conductivity
increases
decreases
remains same
becomes zero
Work of invertor is
to change AC into DC
to change DC into AC
to regulate voltage
None of the above
A battery of four cells in series,each having an emf of 1 .4 V and an internal resistance of 2 is to be used to charge a small 2 V accumulator of negligible internal resistance. What is the charging current?
0.1 A
0.2 A
0.3 A
0.45 A
