1.
Which of the following is the correct decimal power that corresponds to the prefix nano ?
Correct Answer
D. 10^{-9}
Explanation
The prefix nano corresponds to a decimal power of 10-9. The prefix nano is used to denote one billionth of a unit. In scientific notation, this is represented by multiplying the base unit by 10 raised to the power of -9. Therefore, the correct answer is 10-9.
2.
27 °C is equal ___ °k :
Correct Answer
A. 300 °k
Explanation
To convert Celsius to Kelvin, you need to add 273. So, to convert 27 Â°C to Kelvin, you add 273 to get 300 Â°K.
3.
The SI Unit for amount of substance:
Correct Answer
B. Mole
Explanation
The SI unit for amount of substance is mole. The mole is a unit of measurement that represents the amount of a substance. It is defined as the amount of a substance that contains the same number of entities (such as atoms, molecules, or ions) as there are atoms in 12 grams of carbon-12. The mole is widely used in chemistry and is essential for calculating and comparing the amounts of different substances in chemical reactions.
4.
The following measured number
64100 ± 10 can be expressed ( to the correct significant figures) as :
Correct Answer
C. 6.410 x 10^{4}
Explanation
The given measured number, 64100 Â± 10, can be expressed to the correct significant figures as 6.410 x 104. This is because the significant figures are determined by the digits that are known with certainty plus one estimated digit. In this case, the digits 6, 4, 1, and 0 are known with certainty, and the digit 0 is estimated. Therefore, the number is expressed as 6.410 x 104, where 6.410 is the number known with certainty and 104 represents the power of 10.
5.
The density of copper is 3.4 g/cm^{3} . If a cube of copper weighs 20.4 g . What is the length of the edge of the cube ?
Correct Answer
B. 1.82 cm
Explanation
The density of a substance is defined as the mass of the substance per unit volume. In this question, we are given the density of copper (3.4 g/cm3) and the weight of a cube of copper (20.4 g). To find the length of the edge of the cube, we can use the formula: density = mass/volume. Rearranging the formula to solve for volume, we get: volume = mass/density. Substituting the given values, we have: volume = 20.4 g / 3.4 g/cm3 = 6 cm3. Since the cube has equal length, width, and height, the length of the edge of the cube is the cube root of the volume, which is approximately 1.82 cm.
6.
Convert 50 °k to the Fahrenheit scale.
Correct Answer
C. - 378 °F
Explanation
To convert Kelvin to Fahrenheit, you can use the formula: F = (K - 273.15) * 9/5 + 32. Plugging in the given value of 50 K, we get: F = (50 - 273.15) * 9/5 + 32 = -378 Â°F.
7.
Convert 2 km/h to m/s ( to the correct significant figures ):
Correct Answer
B. 0.6
Explanation
To convert km/h to m/s, we need to multiply the value by 1000/3600, as there are 1000 meters in a kilometer and 3600 seconds in an hour. When we calculate 2 km/h to m/s, we get 0.5556 m/s. However, since the question asks for the answer to the correct significant figures, we round it to one decimal place, resulting in 0.6 m/s.
8.
“ The closely individual measurement agree with the true or correct value “ . Is :
Correct Answer
A. Accuracy
Explanation
Accuracy is the correct answer because it refers to how close individual measurements are to the true or correct value. It is a measure of how well the measurements reflect the true value, regardless of how close they are to each other. Precision, on the other hand, refers to how close multiple measurements are to each other, regardless of their closeness to the true value. Therefore, accuracy is the most appropriate term to describe the given statement.
9.
The answer of this operation ( 19.6 + 7.8 )( 9.672 - 5.24 ) =
Correct Answer
B. 121
Explanation
The given expression is a multiplication operation of two sets of parentheses. The first set contains the sum of 19.6 and 7.8, which equals 27.4. The second set contains the difference between 9.672 and 5.24, which equals 4.432. Multiplying these two values together gives us 121.4. Therefore, the correct answer is 121.
10.
Round 1467 to three significant figures :
Correct Answer
C. 1470
Explanation
To round 1467 to three significant figures, we start from the leftmost digit and count three digits, including any zeros. In this case, the leftmost digit is 1, and the next two digits are 4 and 6. Since the digit after 6 is 7, we round up the last digit, which is 6, to the nearest whole number. Therefore, the rounded number is 1470.