Question
What are permanent magnets? Give one example.

Answer

Substances, which at room temperature, retain their ferromagnetic property for a long period of time are called permanent magnets. Alnico, cobalt, steel and ticonal.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Define the term 'activity' of radionuclide. Write its SI unit.
The graph shows variation of stopping potential $V_0$ versus frequency of incident radiation v for two photosensitive metals A and B. Which of the two metals has higher threshold frequency and why?
Magnetic scalar potential is defined as$\text{U}(\overrightarrow{\text{r}_2})-\text{U}(\overrightarrow{\text{r}_1})=-\int\limits^{\vec{\text{r}}_2}_{\vec{\text{r}_1}} \vec{\text{B}}.\text{d}\vec{\text{l}}.$
Apply this equation to a closed curve enclosing a long atraicht wire. The RHS of the above equation is then $-{\mu}_\text{o} \text{ i}$ by Ampere's law. We see that $\text{U}(\vec{\text{r}_2})\neq\text{U}(\vec{\text{r}_1})$ even when $\vec{\text{r}_2}=\vec{\text{r}_1}.$Can we have a magnetic acalar potential in this case?
To measure the magnetic moment of a bar magnet, one may use:
Among alpha, beta and gamma radiations, which get affected by electric field?
A scooter weighing 150kg together with its rider moving at 36km/ hr is to take a turn of radius 30m. What horizontal force on the scooter is needed to make the turn possible?
A Kundt's tube apparatus has a copper rod of length 1.0m clamped at 25cm from one of the ends. The tube contains air in which the speed of sound is 340m/s. The powder collects in heaps separated by a distance of 5.0cm. Find the speed of sound waves in copper.
A source emits 45 joules of energy in 15s. What is the radiant flux of the source?
Two coils $P$ and $Q$ are shown in the figure given. What will be the direction of momentarily induced current in coil $Q$ when (i) switch $K$ is closed and (ii) switch $K$ is again opened after some time?
Image
If we walk barefoot on a nylon mat for some time and touch the metal handle of a door, we get an electric shock. Why does this happen?