Question

what percentage of ac power must be converted to dc power in pcs according to the 2007 energy star® standards?
65%
50%
80%
90%
what is a significant portion of it expenditure?
power expenses
hardware costs
internet connectivity fees
software licensing fees
what is the main challenge with current climate models?
unreliability in predicting sea ice and cloud changes
lack of historical data
inability to measure co2 levels accurately
inconsistent global temperature readings
what is a strong password policy?
using a mix of characters and changing regularly
avoiding the use of special characters
using the same password for all accounts
writing passwords down for easy access

Explanation:

• Question 39: According to the 2007 Energy Star standards, 80% of AC power must be converted to DC power in PCs. This is a standard value from the Energy Star guidelines for power supply efficiency in PCs.
• Question 40: Power expenses are a significant portion of IT expenditure. As IT systems (servers, PCs, etc.) consume a large amount of electricity, the cost of powering these systems (including cooling in data - centers) forms a major part of IT budgets.
• Question 41: The main challenge with current climate models is the unreliability in predicting sea ice and cloud changes. Sea ice and cloud cover have complex interactions with the climate system (e.g., albedo effects for sea ice and radiative effects for clouds), and accurately modeling these in climate models is difficult.
• Question 42: A strong password policy involves using a mix of characters (letters - both upper and lower case, numbers, special characters) and changing passwords regularly. This increases the complexity of passwords, making them harder to crack through brute - force or dictionary attacks. Avoiding special characters weakens passwords, using the same password for all accounts is a security risk (if one account is compromised, all are at risk), and writing passwords down is a physical security risk.

Answer:

• 39: 80%
• 40: Power expenses
• 41: Unreliability in predicting sea ice and cloud changes
• 42: Using a mix of characters and changing regularly