Explanation:
Extremely high temps needed for fusion because K.E. should large enough to overcome repulsion between nuclei.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Demagnetisation of magnets can be done by
| (a) Rough handling | (b) Heating |
| (c) Magnetising in the opposite direction | (d) All the above |
The current i in an induction coil varies with time t according to the graph shown
in figure. Which of the following graphs shows the induced emf (e) in the coil with time
|
(a)
|
(b)
|
(c) |
(d)
|
Cyclotron is used to accelerate
|
(a) Electrons |
(b) Neutrons |
(c) Positive ions |
(d) Negative ions |
In the circuit shown here 
and battery B = 20V. The switch 
is first closed. It is then opened and afterwards 
is closed. What is the charge finally on 
|
(a) 120 μC |
(b) 80 μC |
(c) 40 μC |
(d) 20 μC |
Potential gradient is defined as
|
(a) Fall of potential per unit length of the wire |
|
(b) Fall of potential per unit area of the wire |
|
(b) Fall of potential per unit area of the wire |
|
(d) Potential at any one end of the wire |
A proton moving with a velocity, 2.5 
, enters a magnetic field of intensity 2.5T making an angle 30° with the magnetic field. The force on the proton is
|
(a) 3 |
(b) 5 |
(c) 6 |
(d) 9 |
$\overrightarrow{\text{F}}\times\overrightarrow{\text{a}}$
$\overrightarrow{\text{v}}\times\overrightarrow{\text{r}}$
$\overrightarrow{\text{a}}\times\overrightarrow{\text{r}}$
$\overrightarrow{\text{F}}\times\overrightarrow{\text{r}}$
The area of the plates of a parallel plate condenser is A and the distance between the plates is 10 mm. There are two dielectric sheets in it, one of dielectric constant 10 and thickness 6mm and the other of dielectric constant 5 and thickness 4mm. The capacity of the condenser is
|
(a) |
(b) |
(c) |
(d) 1500 |
A transformer has 100 turns in the primary coil and carries 8 A current. If input power is one kilowatt, the number of turns required in the secondary coil to have 500V output will be
|
(a) 100 |
(b) 200 |
(c) 400 |
(d) 300 |
