Four identical electrical lamps are labelled $1.5\,V$, $0.5\,A$ which describes the condition necessary for them to operate at normal brightness. A $12\,V$ battery of negligible internal resistance is connected to lamps as shown, then
  • AThe value of $R$ for normal brightness of each lamp is $(3/4)$ $\Omega$
  • BThe value of $R$ for normal brightness of each lamp is $(21/4)$ $\Omega$
  • CTotal power dissipated in circuit when all lamps are normally bright is $24\,W$
  • DPower dissipated in $R$ is $21\,W$ when all lamps are normally bright
Medium
art

Download our app
and get started for free

Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*

Similar Questions

  • 1
    In a conductor $4$ coulombs of charge flows for $2$ seconds. The value of electric current will be
    View Solution
  • 2
    A wire of radius $r$ has resistance $R$. If it is stretched to a radius of $\frac{{3r}}{4}$, its resistance becomes
    View Solution
  • 3
    A new flashlight cell of $e.m.f.$ $1.5\, volts$ gives a current of $15\, amps$, when connected directly to an ammeter of resistance $0.04\,\Omega $. The internal resistance of cell is ........... $\Omega$ 
    View Solution
  • 4
    The internal resistance of a primary cell is $4\, ohm$. It generates a current of $0.2\, amp$ in an external resistance of $21\, ohm$. The rate at which chemical energy is consumed in providing the current is .............. $J/s$
    View Solution
  • 5
    A wire of resistance $R$ and radius $r$ is stretched till its radius became $r / 2$. If new resistance of the stretched wire is $x R$, then value of $x$ is $\qquad$
    View Solution
  • 6
    The total current supplied to the circuit by the battery is ............. $A$
    View Solution
  • 7
    Say switches $S_1, S_2$ and so on upto $S_6$ are closed, one after other in order (first $S_1$, then $S_2$) at regular intervals of $1$ minute starting from $t = 0$. The graph of current versus time is best represented as
    View Solution
  • 8
    A railway compartment is lit up by thirteen lamps each taking $2.1\, amp$ at $15\, volts$. The heat generated per second in each lamp will be ............ $cal$
    View Solution
  • 9
    In a potentiometer experiment shown here, for the position $X$ of the jockey $J,$ there occurs a null deflection in the galvanometer. Then the potential difference between points $A$ and $X$ is  ................ $V$
    View Solution
  • 10
    Potential difference across the $40\,\Omega $ resistance will be ............ $V$
    View Solution