MCQ
Inverse square law for illuminance is valid for
- ✓Isotropic point source
- BCylindrical source
- CSearch light
- DAll types of sources
✓
Answer
Correct option: A.
Isotropic point source
a
(a) Inverse square law for illuminance is valid and can be applied for all types of sources.
(a) Inverse square law for illuminance is valid and can be applied for all types of sources.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
The potential energy of a simple harmonic oscillator of mass $2\, kg$ in its mean position is $5\, J.$ If its total energy is $9\,J$ and its amplitude is $0.01\, m,$ its time period would be
→In the following figure, four curves $A, B, C$ and $D$ are shown. The curves are
→A string is used to pull a block of mass $m$ vertically up by a distance $h$ at a constant acceleration $\frac{g}{4}$. The work done by the tension in the string is ...............
→Three particles are situated on a light and rigid rod along $Y$axis as shown in the figure. If the system is rotating with an angular velocity of $2\,rad/\sec $about $X$axis, then the total kinetic energy of the system is ...... $J$
→Figure $(i)$ below shows a Wheatstone's bridge in which $P, Q, R$ and $S$ are fixed resistances, $G$ is a galvanometer and $B$ is a battery. For this particular case, the galvanometer shows zero deflection. Now, only the positions of $B$ and $G$ are interchanged, as shown in figure $(ii)$. The new deflection of the galvanometer
→What is the moment of inertia of a square sheet of side $l$ and mass per unit area $\mu $ about an axis passing through the centre and perpendicular to its plane
→A solid copper sphere (density $\rho $ and specific heat capacity $c$ ) of radius $r$ at an initial temperature $200K$ is suspended inside a chamber whose walls are at almost $0K$ . The time required (in $\mu s$) for the temperature of the sphere to drop to $100\, K$ is
→Two balls $A$ and $B$ are thrown with same velocity $u$ from the top of a tower. Ball $A$ is thrown vertically upwards and the ball $B$ is thrown vertically downwards. If $t_A$ and $t_B$ are the respective times taken by the balls $A$ and $B$ respectively to reach the ground, then identify the correct statement
→In a series $L-C-R$ circuit the frequency of a $10\,volt$ $a.c.$ voltage source is adjusted in such a fashion that the reactance of the inductor measures $15\,\Omega $ and that of the capacitor $11\,\Omega $. If $R = 3\,\Omega $, the potential difference across the series combination of $L$ and $C$ will be.....$V$
→If the length of a stretched string is shortened by $40\%$ and the tension is increased by $44\%$, then the ratio of the final and initial fundamental frequencies is
→