EASY
12th West Bengal Board
IMPORTANT
Earn 100

  If the discharged battery is charged by an external emf source, is the terminal voltage of the battery during charging greater or less than 12 V ?

Important Questions on Current Electricity

HARD
12th West Bengal Board
IMPORTANT

A variable rheostat of 2 , Fig. is used to control the p.d. across a 500 Ω load RL. If the resistance A B is 500 Ω, what is p.d. across RL? If RL is removed, what should be the resistance B C to get 40 V between B and C.

 

HARD
12th West Bengal Board
IMPORTANT
A heating element using nichrome connected to a 230 V supply draws an initial current of 3.2 A which settles after a few second to a steady value of 2.8 A. Find the steady temperature of the heating element. If the room temperature is 27° C. The temperature co-efficient of resistance of nichrome averaged over the temperature range involved in 1.70×10-4C-1.
 
HARD
12th West Bengal Board
IMPORTANT
 Calculate the conductance and conductivity of the material of a wire of resistance 0.01 Ω, area of cross-section 10-4 m2 and length 0.1 m
 
MEDIUM
12th West Bengal Board
IMPORTANT
 Calculate the resistivity of the material of a wire 1.0 m long, 0.4 mm in diameter and having a resistance of 2.0 ohm
HARD
12th West Bengal Board
IMPORTANT
A voltage of 30 V is applied across a carbon resistor with first, second and third rings of blue, black and yellow colours respectively. Calculate the value of the current in mA through the resistor.
HARD
12th West Bengal Board
IMPORTANT

In the given network of Fig. 5.133,R1=100Ω,R2=R3=50ΩR4=75 Ω and E=6.0 V Find the currents in each resistor.Question Image

 

 

MEDIUM
12th West Bengal Board
IMPORTANT
You are given 'n' resistors, each resistance 'r'. These are first connected to get minimum possible resistance. In the second case, these are again connected differently to get maximum possible resistance. Compute the ratio between minimum and maximum values of resistance so obtained.
HARD
12th West Bengal Board
IMPORTANT

Calculate the equivalent resistance between the points A and B of the following network of conductors in Fig.

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