All Exams Test series for 1 year @ ₹349 only
Question

On a summer day, a scooter rider feels more comfortable while on the move than while at a stop light because ____

The correct answer is
More heat is lost by convection and radiation while in motion

Scooter Rider Comfort Explained

A scooter rider feels more comfortable when moving compared to being stopped because of improved heat dissipation from the body.

Heat Transfer Principles

Human bodies generate heat continuously through metabolic processes. Maintaining a comfortable body temperature requires balancing heat generated internally and absorbed from the environment with heat lost to the surroundings. Key heat loss mechanisms are convection, radiation, evaporation, and conduction.

Motion Enhances Heat Loss

  • Convection: When the scooter is in motion, air moves rapidly across the rider's body. This increased airflow sweeps away the layer of warm air surrounding the body, replacing it with cooler ambient air. This significantly boosts heat loss via convection.
  • Radiation: While convection is dominant, the constant airflow also aids in heat loss through radiation by preventing the build-up of a hot micro-environment around the rider.

Stillness Reduces Heat Loss

When the scooter stops (e.g., at a traffic light), the airflow over the rider's body drastically reduces. This lack of air movement greatly diminishes heat loss through convection. As the body continues to generate heat, it accumulates, leading to a feeling of warmth and discomfort.

Conclusion

Therefore, the primary reason for increased comfort while moving is the enhanced rate of heat loss through convection and radiation due to the forced airflow. This aligns with the principle that more heat is lost by convection and radiation while in motion.

Correct Option Analysis:

Option C correctly identifies that more heat is lost by convection and radiation while in motion, which directly explains the increased comfort felt by the rider.

Was this answer helpful?

Important Questions from Convection

  1. Heat transfer in liquid and gases take place by _______

  2. In cooling tower, water is cooled by the process of ________.

  3. The ratio of the thickness of the thermal boundary layer to the thickness of the hydrodynamic boundary layer is equal to (Prandtl number)n, where n is______.

  4. In regarding nucleate boiling _______.

  5. In natural convection heat transfer, Nusselt number is a function of:

Need Expert Advice?

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App