1.Easy
A solenoid 12 cm long has 2000 turns. Which current I gives a magnetic flux density of 20.94 mT inside it?
N = 2000L = 12 cmB = 20.94 mTμ₀ = 4π × 10⁻⁷ T·m/A
I = A
Magnetic fields & induction worksheet with answers
2.Easy
A solenoid 20 cm long has 2000 turns. Which current I gives a magnetic flux density of 50.27 mT inside it?
N = 2000L = 20 cmB = 50.27 mTμ₀ = 4π × 10⁻⁷ T·m/A
I = A
3.Medium
A proton moves at 6 × 10⁵ m/s perpendicular to a uniform magnetic field of 0.8 T. Find the radius r of its circular path.
m = 1.673 × 10⁻²⁷ kg|q| = 1.602 × 10⁻¹⁹ Cv = 6 × 10⁵ m/sB = 0.8 T
r = cm
4.Medium
An alpha particle moving at 4 × 10⁵ m/s enters a uniform magnetic field at right angles and moves on a circle of radius 8.296 cm. Find the magnetic flux density B.
m = 6.645 × 10⁻²⁷ kg|q| = 3.204 × 10⁻¹⁹ Cv = 4 × 10⁵ m/sr = 8.296 cm
B = T
5.Hard
An alpha particle starts from rest, is accelerated through a potential difference of 10000 V and then enters a uniform magnetic field of 0.2 T at right angles. Find the radius r of its path in the field.
m = 6.645 × 10⁻²⁷ kg|q| = 3.204 × 10⁻¹⁹ CV = 10000 VB = 0.2 T
r = cm
6.Hard
An alpha particle passes undeflected through a velocity selector with crossed fields E = 1 × 10⁵ V/m and B₁ = 0.05 T. It then enters a second region with only a magnetic field B₂ = 0.8 T, at right angles. Find the radius r of its path there.
E = 1 × 10⁵ V/mB1 = 0.05 TB2 = 0.8 Tm = 6.645 × 10⁻²⁷ kg|q| = 3.204 × 10⁻¹⁹ C
r = cm
Answer key
- 1. I = 0.9998 A
- 2. I = 4 A
- 3. r = 0.7832 cm
- 4. B = 0.1 T
- 5. r = 10.18 cm
- 6. r = 5.185 cm
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