Haematite, magnetite, limonite and siderite are types of which mineral?

A. Coal
B. Iron
C. Copper
D. Aluminium

Answer

Correct Answer: B. Iron

Detailed About MCQs

Iron is one of the most important metals of the modern age and it is extracted from a number of ores. However, the commercial production comes only from four types of ores namely:
Haematite (Fe203)
Magnetite (Fe304)
Limonite and
Siderite (FeC03)

A simple microscope consists of which lenses?

A. a long-focus concave lens
B. a short-focus concave lens
C. a short-focus convex lens
D. a long-focus convex lens

Answer

Correct Answer: C. A short-focus convex lens 

Detailed About MCQs

The use of a single short-focus convex lens or groups of lenses are found in simple magnification devices such as the magnifying glass, loupes, and eyepieces for telescopes and microscopes. If a convex lens is held close to a person’s eyes, they will see an image that is upright and larger than the actual object.

The power we use at Home has a frequency of 60Hz. What would be the period of the sine wave?

A. 0.116 seconds
B. 0.0016 Microseconds
C. 0.0116 seconds
D. 0.0116 Microseconds

Answer

Correct Answer: C. 0.0116 seconds

Detailed About MCQs

When the power we use at Home has a frequency of 60Hz, the sine wave period is equal to 0.0116 seconds. The period of the sine curve is the length of one cycle of the curve.