A Metal Ball of Radius 0

question 40

Multiple Choice

A metal ball of radius 0.1 m at a uniform temperature of 90°C is left in air at 30°C. The density and the specific heat of the metal are 3000 kg/m³ and 0.4 kJ/kg.K respectively. The heat transfer co-efficient is 50 W/m².K Neglecting the temperature gradients inside the ball, the time taken (in hours) for the ball to cool to 60°C is

• A)555
• B)55.5
• C)0.55
• D)0.15

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Definitions:

Anything Goes Mentality

A laissez-faire attitude towards rules and norms, suggesting that all actions are permissible regardless of morals or consequences.

Positively Valued Stimuli

Objects, conditions, or experiences that are considered desirable or beneficial by a person or within a culture.

Criminal Victimization

The process or event of being harmed or negatively impacted by a criminal act.

Deterrence Doctrine

A theory that policies or threats of punitive action can discourage or prevent individuals or states from engaging in undesirable behavior, such as committing crimes or waging war.