Mica is a ____ conductor of electricity.

A slit of width is illuminated by white light. For red light $\left(\lambda =6500\mathring{A}\right)$, the first minima is obtained at $\theta ={30}^{\circ }.$ Then the value of will be

The potential at a point x ( measured in $\mu$ m) due to some charges situated on the x-axis is given by
$V\left(x\right)=20/\left(x^2-4\right)volt$

The half-lives of radioactive sample are 30 years and 60 years for two decay processes. If the sample decays by both the processes simultaneously. The time after which, only one-fourth of the sample will remain is

Two periodic waves of intensities $I_1$ and $I_2$ pass through a region at the same time in the same direction. The sum of the maximum and minimum intensities is

A slit of size $0.15m$ is placed at $2.1m$ from a screen. On illuminated it by a light of wavelength $5\times {10}^{-5}cm.$ The width of central maxima will be

An electric charge ${10}^{-3}\mu C$ is placed at the origin (0, 0) of X-Y co-ordinate system. Two points A and B are situated at $\left(\sqrt{2},\sqrt{2}\right)$ and (2, 0) respectively. The potential difference between the points A and B will be

$A\text{and}B$ two metallic rings pplaced at opposite sides of an infinitely long straight conducting wire as shown in Fig. 3.157. If current in the wire is slowly decreased, the direction of the induced current will be

The breakdown in a reverse biased p-n junction diode is more likely to occur due to

A $200W$ and a $100W$ , both meant for operation a t $220V$ are connected to a $220V$ supply. The total power consumed by them will be
(i) 300W, if connected in series
(ii) 300W, if connected in parallel
(iii) $\frac{200}{3}W$, if connected in series
(iv) $\frac{200}{3}W$, if connected in parallel