- A 12 V battery is connected across a 2 ohm resistor. Enter the current in ampere.
Answer and explanation
Using Ohm's law, ampere.
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Using Ohm's law, ampere.
Length
Force
Thermodynamic temperature
Pressure

Length and thermodynamic temperature are SI base quantities. Force and pressure are derived quantities.
30 cm
40 cm
60 cm
20 cm
Using lens formula: , solve for u.
Left-hand rule
Right-hand thumb rule
Fleming’s left-hand rule
None of these
Right-hand thumb rule determines the field direction.
0°C
32°C
100°C
-273°C
Water freezes at 0°C.
Frequency
Sound intensity
Wavelength
Speed
Sound intensity (loudness) is measured in decibels.
V = I/R
V = IR
V = R/I
V = I + R
Formula:
Motion changes without any force
Rest and motion continue until an external force acts
Only valid for planets
Only applies in vacuum
Law of Inertia: A body remains at rest or in uniform motion unless acted upon by an external force.
Convex lens
Concave lens
Cylindrical lens
Plano-convex lens
Concave lenses are used to correct myopia because they diverge light rays before reaching the eye.
Zeroth law
First law
Second law
Third law
The First Law of Thermodynamics states that energy can neither be created nor destroyed, only transformed.
Galileo Galilei
Albert Einstein
Isaac Newton
James Clerk Maxwell
Sir Isaac Newton introduced the three fundamental laws of motion.
IR
I/R
R/I
I+R
Ohm’s law states that V = IR, where V is voltage, I is current, and R is resistance.
Solid
Liquid
Gas
Vacuum
Sound requires a medium (solid, liquid, or gas) to travel, so it cannot travel through a vacuum.
Where:

0° - No reflection occurs
45° - When incident angle is 45°k
90° - Perpendicular to surface
180° - Complete reversal
Law of Reflection: The angle of reflection equals the angle of incidence.
| 📐 Incident Angle | 🔄 Reflected Angle | 🪞 Surface Type | ✅ Verification |
|---|---|---|---|
| 30° | 30° | Plane Mirror | θᵣ = θᵢ |
| 45° | 45° | Plane Mirror | θᵣ = θᵢ |
| 60° | 60° | Plane Mirror | θᵣ = θᵢ |
💡 Note: This fundamental law forms the basis for understanding mirrors, periscopes, and many optical instruments used in physics.
Where:

0° - No reflection occurs
45° - When incident angle is 45°k
90° - Perpendicular to surface
180° - Complete reversal
Law of Reflection: The angle of reflection equals the angle of incidence.
| 📐 Incident Angle | 🔄 Reflected Angle | 🪞 Surface Type | ✅ Verification |
|---|---|---|---|
| 30° | 30° | Plane Mirror | θᵣ = θᵢ |
| 45° | 45° | Plane Mirror | θᵣ = θᵢ |
| 60° | 60° | Plane Mirror | θᵣ = θᵢ |
💡 Note: This fundamental law forms the basis for understanding mirrors, periscopes, and many optical instruments used in physics.