The circuit shown contains a $12 \ V$ battery,a $4 \ \Omega$ resistor,and two branches in parallel,each containing an ideal diode and a resistor. Branch $1$ has diode $D_1$ and a $3 \ \Omega$ resistor,while branch $2$ has diode $D_2$ and a $2 \ \Omega$ resistor. Determine the total current flowing in the circuit. (in $A$)

The output characteristics of an $n-p-n$ transistor represent,($I_C=$ collector current,$V_{C E}=$ potential difference between collector and emitter,$I_B=$ base current,$V_{B B}=$ voltage given to base,$V_{B E}=$ the potential difference between base and emitter)

If the direction ratios of two lines are given by $3lm - 4ln + mn = 0$ and $l + 2m + 3n = 0$, then the angle between the lines is:

What are the substances which mimic the natural chemical messengers?

When a light of a given wavelength falls on a metallic surface the stopping potential for photoelectrons is $3.2 \ V$. If a second light having wavelength twice of first light is used, the stopping potential drops to $0.7 \ V$. The wavelength of first light is . . . . . . $m$.
$(h = 6.63 \times 10^{-34} \ J.s, e = 1.6 \times 10^{-19} \ C, c = 3 \times 10^8 \ m/s)$

If the altitudes of a triangle are in arithmetic progression,then the sides of the triangle are in