Which of the following is not aromatic?

When radiation of wavelength $\lambda$ is incident on a metallic surface,the stopping potential is $4.8 \ V$. If the same surface is illuminated with radiation of double the wavelength,then the stopping potential becomes $1.6 \ V$. Then the threshold wavelength for the surface is

Which of the following chambers of the human heart has the thickest wall?

$A$ man measures the period of a simple pendulum inside a stationary lift and finds it to be $T \ s$. If the lift accelerates upwards with an acceleration $g/4$,then the period of the pendulum will be

Along the $x$-axis,three charges $\frac{q}{2}, -q$ and $\frac{q}{2}$ are placed at $x=0, x=a$ and $x=2a$ respectively. The resultant electric potential at a point $P$ located at a distance $r$ from the charge $-q$ (where $r > a$) is ($\varepsilon_0$ is the permittivity of free space):

$A$ driver applies the brakes on seeing the red traffic signal $400 ~m$ ahead. At the time of applying the brakes,the vehicle was moving with $15 ~m/s$ and retarding at $0.3 ~m/s^2$. The distance covered by the vehicle from the traffic light $1$ minute after the application of brakes is (in $~m$)