Remote Sensing

Step 1: Identify the sensors on the IRS-1C satellite.
IRS-1C, a significant satellite in the Indian Remote Sensing program, carried three main imaging sensors:
1. Panchromatic Camera (PAN)
2. Linear Imaging Self-Scanning Sensor (LISS-III)
3. Wide Field Sensor (WiFS)
Step 2: Determine the number of spectral bands for the primary multispectral sensor.
The question is likely referring to the primary operational multispectral sensor, which is LISS-III. The LISS-III sensor operates in four spectral bands:
- Band 2: Green (0.52 - 0.59 m)
- Band 3: Red (0.62 - 0.68 m)
- Band 4: Near-Infrared (NIR) (0.77 - 0.86 m)
- Band 5: Short-Wave Infrared (SWIR) (1.55 - 1.70 m)
The PAN sensor operates in a single, wide panchromatic band. The WiFS sensor operates in two bands (Red and NIR). Given the options, the question is best answered by considering the number of bands in the LISS-III sensor.

Step 1: Identify the part of the electromagnetic (EM) spectrum visible to humans. This portion is known as the visible spectrum. It's the range of wavelengths of light that the human eye can perceive, corresponding to the colors of the rainbow.
Step 2: State the wavelength range of the visible spectrum. The visible spectrum typically ranges from approximately 400 nanometers (nm) for violet light to about 700 nanometers (nm) for red light.
Step 3: Convert this range to meters.
We know that 1 nm = 10 m.
- 400 nm = 400 10 m = 0.4 10 m
- 700 nm = 700 10 m = 0.7 10 m
So, the range is from 0.4 10 m to 0.7 10 m. This is also commonly written as 0.4 to 0.7 micrometers ( m).