Daily Practice Questions

Explanation: Closing switch $S_1$ creates a parallel path that reduces the total circuit resistance and increases current, but it does not alter the voltage across or current through the top bulb, so its intensity remains unchanged. In contrast, closing switch $S_2$ completes a short circuit directly across the battery terminals; this causes the entire circuit current to bypass the bulbs entirely, causing the top bulb to go out completely. This scenario tests the concepts of parallel circuits, equivalent resistance, and the effects of short circuits on voltage distribution.

Explanation: This problem tests the Side-Angle-Side (SAS) congruence postulate, which requires the angle to be included between the two known sides. In $\triangle ABC$, the sides of length 6 and 7 meet at vertex $B$, so the included angle is $\angle ABC$. For $\triangle DEF$ to be congruent via SAS, the corresponding included angle must also be equal. Since the problem states the sides are 6 and 7, the angle between them in $\triangle DEF$ is $\angle DFE$ (assuming standard correspondence where $D$ corresponds to $A$, $E$ to $B$, and $F$ to $C$, or simply identifying the vertex between the 6 and 7 sides). Option (C) provides this specific included angle equality.

Explanation: Suppose that n = 365051. The method call writeWithCommas(365051) will write 051 and then execute the call writeWithCommas(365) . This is a base case, so 365 will be written out, resulting in 051,365 . A number like 278278 (two sets of three identical digits) will be written out correctly, as will a “symmetrical” number like 251462251. Also, any n < 1000 is a base case and the number will be written out correctly as is.

Explanation: The explanation contributes to the image of the speaker as a gentleman with well-defined culinary tastes. The other choices refer to eating but not specifically to the speaker’s predilections for certain foods.

Explanation: Transcription by RNA polymerase is the only process listed that occurs in both prokaryotes and eukaryotes, as all living cells require this enzyme to synthesize RNA from a DNA template. In contrast, alternative splicing of exons, the addition of a 5′ GTP cap, and the addition of a 3′ poly-A tail are post-transcriptional modifications that occur exclusively in eukaryotic cells to process mRNA before it leaves the nucleus. Therefore, option (D) is the correct answer because it represents a fundamental cellular mechanism shared across both domains of life.

Explanation: The balanced equation is $2\text{HgO} \rightarrow 2\text{Hg} + \text{O}_2$. First, calculate moles of $\text{HgO}$: $4.32 \text{ g} / 216 \text{ g mol}^{-1} = 0.0200 \text{ mol}$. The stoichiometric ratio is 2 mol $\text{HgO}$ to 1 mol $\text{O}_2$, so moles of $\text{O}_2 = 0.0200 / 2 = 0.0100 \text{ mol}$. Choice (C) is a common error resulting from forgetting to divide by the coefficient 2.