Tag: earthquake

The answer is D.

The decibel (dB) is a logarithmic unit used to express the ratio between two values of a physical quantity, often power or intensity. One of these quantities is often a reference value, and in this case, the decibel can be used to express the absolute level of the physical quantity, as in the case of sound pressure. The number of decibels is ten times the logarithm to base 10 of the ratio of two power quantities, or of the ratio of the squares of two field amplitude quantities.
The Richter scale is not a linear scale. This means that an earthquake of magnitude 6 does not have twice as destructive power as the earthquake of magnitude 3. Actually, an earthquake with magnitude 5 is ten times more destructive than an earthquake of magnitude 4. The Richter scale is a logarithmic scale.
The Meter scale is a linear scale.
Hence, (i) and (ii) are non-linear scales.

A seismograph or seismometer is an instrument which is used to record the direction of movement of earthquake waves. The first seismograph was invented in 132 A.D. by the Chinese astronomer and mathematician Chang Heng.

All three following instruments are useful in measuring the seismic activity under the earth's surface. A seismometer is an instrument that responds to ground motions, such as caused by earthquakes, volcanic eruptions. Richter scale a quantitative measure of an earthquake's magnitude. The modified Mercalli intensity scale also measures the effect of an earthquake on the Earth's surface. 

The modified Mercalli intensity scale also measures the effect of an earthquake on the Earth's surface. The Mercalli scale grades the earthquake on a 12-point scale. The intensity scale helps to analyze the data by constructing isoseismal curves, which are lines that connect points of equal intensity. 

• There are a number of ways to measure the magnitude of an earthquake. The first widely-used method, the Richter scale, was developed by Charles F. Richter in 1934. It used a formula based on the amplitude of the largest wave recorded on a specific type of seismometer and the distance between the earthquake and the seismometer.
  
• Another way to measure the strength of an earthquake is to use the Mercalli scale. Invented by Giuseppe Mercalli in 1902, this scale uses the observations of the people who experienced the earthquake to estimate its intensity.
  

Pressure is the force applied perpendicular to the surface of an object per unit area over which that force is distributed.

Decibel is a unit used to measure the intensity of a sound or the power level of an electrical signal by comparing it with a given level on a logarithmic scale.

The Richter magnitude scale (also Richter scale) assigns a magnitude number to quantify the size of an earthquake.

Kaleidoscope operates on the principle of multiple reflection, where two or more reflectors are placed at an angle to one another. When the eye is placed at one end of the reflectors, the original view from the aperture on the other side is multiplied into a symmetrical mosaic pattern. A two-mirror kaleidoscope yields a circular pattern isolated against a solid black background, while the three-mirror equilateral triangle type yields an infinite pattern that fills the entire visual field.

A seismometer is an instrument that responds to ground motions, such as caused by earthquakes, volcanic eruptions, and explosions. Seismometers are usually combined with a timing device and a recording device to form a seismograph

Rotation is the movement of the earth on its axis. The earth takes about 24 hours to complete one rotation on its axis. The period of rotation is known as the earth day. This is the daily motion of the earth.