Physics-Obj
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SECTION B
(8)

(8b cont)

(8e)

(9)

(12)

(4)

(3a)
Stress: Pascal (Pa) or Newton per square meter (N/m²)

(3b)
Force constant (also known as spring constant): Newton per meter (N/m)

(3c)
Planck’s constant: Joule-second (J·s)

(1a)
¥= force/length
Recall, mass= kg= M, length=m = L; time=s= T

So,
Force= mass × acceleration
= mass × velocity/time
= mass × displacement/time × 1/time
= mass × displacement/(time)²
= kg × m/s²
= kgm/s²
Dimension= ML/T²

Length= m
Dimension= L

Thus,
¥= (ML/T²) ÷ L
= ML/T² × 1/L
= ML/LT²
= M/T²

(1b)
gravimeter.

(5)
(i)They are used to make permanent magnets, which are essential in motors, generators, and various electronic devices.
(ii)Ferromagnetic materials are also used in magnetic storage media, including hard drives and magnetic tape, due to their ability to maintain a magnetic state without an external field.
(iii)They are utilized in transformers and inductors, which are critical components in power supplies and electrical circuits, where they enhance the magnetic coupling between coils.

(2a)
(i)Monitoring and studying Earth’s weather and climate by capturing continuous images and data of Earth’s surface and atmosphere.
(ii)Facilitating global communications, especially in high-latitude regions that are difficult to reach with geostationary satellites.

(2b)
The slope of a graph of tensile stress against tensile strain represents the Young’s modulus of the material. This modulus is a measure of the stiffness of the material and is defined as the ratio of tensile stress to tensile strain in the linear portion of the stress-strain curve.