## 1. The SI unit of length is:

### Answer:

### Explanation:

In the International System of Units (SI), the standard unit of length is the meter.

## 2. Which of the following is NOT a fundamental unit?

### Answer:

### Explanation:

Newton is a derived unit of force. The fundamental units are basic units from which other units are derived.

## 3. The number of significant figures in 0.005300 is:

### Answer:

### Explanation:

Only the digits 5, 3 are considered significant. Leading zeros and trailing zeros in a decimal number are not counted as significant figures.

## 4. The SI unit of time is:

### Answer:

### Explanation:

In the International System of Units (SI), the standard unit of time is the second.

## 5. The study of standards for different physical quantities is known as:

### Answer:

### Explanation:

Metrology is the science of measurement and its application.

## 6. What is the value of the speed of light in a vacuum?

### Answer:

### Explanation:

The speed of light in a vacuum is approximately 3 x 10^8 meters per second.

## 7. Which of the following is the smallest measurable length?

### Answer:

### Explanation:

Planck length, approximately 1.6 x 10^-35 meters, is the smallest length scale at which current theories of physics are believed to remain valid.

## 8. The prefix ‘Mega’ denotes:

### Answer:

### Explanation:

In the metric system, the prefix ‘Mega’ denotes a factor of one million, or 10^6.

## 9. Which of the following has the dimension [M^1L^1T^-2]?

### Answer:

### Explanation:

The dimensional formula of force is [M^1L^1T^-2].

## 10. How many base units are there in the SI system?

### Answer:

### Explanation:

There are 7 base units in the SI system: meter, kilogram, second, ampere, kelvin, mole, and candela.

## 11. The unit of luminous intensity in the SI system is:

### Answer:

### Explanation:

Candela is the SI unit of luminous intensity.

## 12. A decibel is a unit used to measure:

### Answer:

### Explanation:

A decibel (dB) is commonly used to express the intensity or level of sound.

## 13. The accuracy of a measurement refers to:

### Answer:

### Explanation:

Accuracy indicates how close a measurement is to the true or accepted value.

## 14. The SI unit of electric current is:

### Answer:

### Explanation:

Ampere is the SI unit of electric current.

## 15. The amount of space occupied by a substance is called its:

### Answer:

### Explanation:

Volume is the quantity of three-dimensional space occupied by a substance or enclosed by a surface.

## 16. Which of these is a unit of frequency?

### Answer:

### Explanation:

Hertz is the SI unit of frequency, defined as one cycle per second.

## 17. The uncertainty in a measurement is known as:

### Answer:

### Explanation:

Error is the difference between the measured value and the true value.

## 18. What does the prefix ‘kilo’ represent?

### Answer:

### Explanation:

In the metric system, the prefix ‘kilo’ denotes a factor of one thousand, or 10^3.

## 19. Which of the following is dimensionless?

### Answer:

### Explanation:

Refractive index is a ratio and hence, it doesn’t have any dimensions.

## 20. The correct representation of the unit of gravitational constant ‘G’ is:

### Answer:

### Explanation:

The gravitational constant, G, has units of m^3kg^-1s^-2.

## 21. A unit that is derived from the fundamental units is called:

### Answer:

### Explanation:

Derived units are combinations of the seven base SI units.

## 22. What represents the precision of an instrument?

### Answer:

### Explanation:

Resolution is the smallest measurable value that an instrument can detect.

## 23. The SI unit of temperature is:

### Answer:

### Explanation:

Kelvin is the SI unit of thermodynamic temperature.

## 24. Which of these is NOT a scalar quantity?

### Answer:

### Explanation:

Velocity has both magnitude and direction, making it a vector quantity.

## 25. The process of determining the value of some quantity in terms of a standard unit is called:

### Answer:

### Explanation:

Measurement is the comparison of an unknown quantity with a known or standard quantity.