Step 1: Understanding the Psychological Effect of Colours.
Blue is known to have a calming and cooling effect on the eyes and mind. It is often associated with coolness, calmness, and tranquility.
Step 2: Verifying the Options.
- Option (1): Blue colour typically produces a cold effect, making this the correct answer.
- Option (2): "General" is not a specific effect for blue.
- Option (3): Blue is not associated with a hot effect.
- Option (4): "None of these" is incorrect because blue does produce a cold effect.
Conclusion:
Therefore, the correct answer is (1) Cold.