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Gravitational Field and Field Strength
A gravitational field is a region in which a mass experiences gravitational force. Gravitational field strength at a point is gravitational force per unit test mass: g = Fm
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Gravitational Field and Field Strength
What is it?
A gravitational field is a region in which a mass experiences gravitational force. Gravitational field strength at a point is gravitational force per unit test mass: g = Fm
In simple words
- `g=GM/r²`
- Direction → toward mass.
- Unit → `N/kg`.
Recommended for Class 12
Full school-level explanation
A gravitational field is a region in which a mass experiences gravitational force. Gravitational field strength at a point is gravitational force per unit test mass: g = Fm
Direction
For a spherical mass `M`, the gravitational force on test mass `m` at distance `r` is: F = GMm/r² Since: g = Fm therefore: g = GM/r² Gravitational field strength is a vector. Its direction is toward the attracting mass.
SI Unit
From: `g = Fm` the unit is: N kg⁻¹ It is also equivalent to: m s⁻²
Field Lines
Gravitational field lines around an isolated spherical mass point radially inward. Where lines are closer together, the field is represented as stronger.
Formula / Key Relation
**g = Fm** **g = GM/r²**
Remember
- toward the attracting mass
- N kg⁻¹
- m s⁻²
- g = Fm
- g = GM/r²
Deeper understanding
Go deeper on Gravitational Field and Field Strength: connect the definition to reasons, relationships, exceptions, and exam wording.
Common mistakes
Exam focus
G ≠ g
Exam focus
Quick revision
- toward the attracting mass
- N kg⁻¹
- m s⁻²
- g = Fm
- Direction: For a spherical mass `M`, the gravitational force on test mass `m` at distance `r` is: **F = GMm/r²
- SI Unit: From: `g = Fm` the unit is: N kg⁻¹ It is also equivalent to: m s⁻²
For long answers on Gravitational Field and Field Strength: define clearly → explain the main parts → give one example → state one exam caution.
Exam Focus
Exam Focus
Important points
- toward the attracting mass
- N kg⁻¹
- m s⁻²
- g = Fm
Important formulas
- toward the attracting mass
- N kg⁻¹
- m s⁻²
Common exam traps
- Do not confuse:
- G** = universal gravitational constant
Long question structure
Definition → key parts → example → exam caution
Common Mistakes
Common Mistakes
- Mistake
Do not confuse:
- Mistake
G** = universal gravitational constant
- Mistake
with
- Mistake
g** = local gravitational field strength.
Revision Zone
60-Second Revision
Quick cues from this topic — use them for last-minute revision.
toward the attracting mass
N kg⁻¹
m s⁻²
g = Fm
A gravitational field is a region in which a mass experiences gravitational force. Gravitational field strength at a point is gravitational force per u
g = Fm
- Definition
- A gravitational field is a region in which a mass experiences gravitational force. Gravitational field strength at a point is gravitational force per u
- Formula
- g = Fm
- Critical warning
- Do not confuse:
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Exam Practice
Define
Q1. Define Gravitational Field and Field Strength.
Explain
Q2. Explain: Direction.
Example
Q3. Give one clear example of Gravitational Field and Field Strength and say why it fits.
Mistake
Q4. State one common mistake students make about Gravitational Field and Field Strength.
Exam note
Q5. Write a short exam note on Gravitational Field and Field Strength: definition, two points, one example.
Sources & References
School-standard facts for Matric and Intermediate. Original explanations — not copied from textbooks.