Tag: science & technology

Quizzes (551) Questions (11015)

Questions Related to science & technology

Multiple choice general knowledge science & technology

The boiling temperature of water is much higher than methane because water molecules are:

  1. composed of fewer atoms

  2. more massive

  3. smaller

  4. polar
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Water has polar molecules with partial positive and negative charges due to oxygen's electronegativity. This allows strong dipole-dipole interactions and hydrogen bonding, requiring more energy (higher temperature) to overcome. Methane is nonpolar with weaker intermolecular forces.

Multiple choice general knowledge science & technology

Are there hydrogen bonds between water molecules in the liquid phase?

  1. No, and if there were, the water would just be ice (a solid)

  2. Yes, and they are continually breaking and reforming

  3. Yes, but they rarely occur

  4. No, otherwise the water molecules would not be able to tumble over one another
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Liquid water does have hydrogen bonds, but they're dynamic and transient - constantly breaking and reforming as water molecules move. This allows fluidity (tumbling motion) while maintaining stronger intermolecular attraction than would exist without hydrogen bonding.

Multiple choice general knowledge science & technology

Detergents differ from soaps in that:

  1. their ionically charged heads are derivatives of sulfur

  2. they can be broken down by microorganisms

  3. detergents are human-made while soaps are produced naturally

  4. detergents are less able to penetrate grease than soaps
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Detergents contain sulfonate groups (sulfur derivatives) in their hydrophilic heads, while soaps use carboxylate groups. Both are biodegradable, soaps can be synthetically produced, and detergents actually penetrate grease better than soaps.

Multiple choice general knowledge science & technology

What is the output of the following: StringBuffer sb1 = new StringBuffer("Amit"); StringBuffer sb2= new StringBuffer("Amit"); String ss1 = "Amit"; System.out.println(sb1==sb2); System.out.println(sb1.equals(sb2)); System.out.println(sb1.equals(ss1)); System.out.println("Poddar".substring(3));

  1. false false false dar

  2. false true false dar

  3. true true false dar

  4. compile-time error
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

sb1==sb2 returns false (different StringBuffer objects). StringBuffer doesn't override equals(), so sb1.equals(sb2) is false. sb1.equals(ss1) is false (different types). "Poddar".substring(3) returns "dar" (from index 3 to end). Output: false false false dar

Multiple choice general knowledge science & technology

What is the output of following code: String s1 = new String("java"); String s2 = s1.replace('a','i'); s1.concat("Fundamentals"); System.out.println(s1); System.out.println((s1+s2).charAt(5));

  1. javaFundamentals u

  2. jivi i

  3. java i

  4. jiviFundamentals u

  5. compile-time error
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Strings are immutable in Java. s1 remains "java" (concat returns new string, not assigned). s2 = "jivi". s1+s2 = "javajivi", charAt(5) = 'i' (0-indexed: j=0, a=1, v=2, a=3, j=4, i=5). Output: "java i"

Multiple choice general knowledge science & technology

What will be the result of compiling and running the given program? Select one correct answer. 1 public class exception 2 { 3 public static void main(String args[]) 4 { 5 System.out.println("A"); 6 try 7 { 8 System.out.println("B"); 9 System.exit(0); 9 } 10 catch(Exception e) 11 { 12 System.out.println("C"); 13 } 14 finally 15 { 16 System.out.println("D"); 17 } 18 } 19 }

  1. Program compiles correctly and prints "A" and "C" when executed

  2. Program compiles correctly and prints "A" when executed

  3. Program compiles correctly and prints "A","B" and "C" when executed

  4. Program compiles correctly and prints "A" and "B" when executed

  5. compile-time error

  6. run-time error
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When System.exit(0) is called, the JVM terminates immediately without executing the finally block. The program prints A (before try), then B (inside try), then exits. The catch block is not executed because no exception is thrown, and finally is not reached because System.exit() terminates the program.

Multiple choice general knowledge science & technology

Given the following: class MyThread extends Thread{ public static void main(String [] args){ MyThread t=new MyThread(); Thread x=new Thread(t); x.start(); public void run(){ for(int i=0;i<3;++i) System.out.print(i+”..”); } } } what is the result of above code?

  1. compile-time error

  2. run-time error

  3. 0..1..2..

  4. 0..1..2..3..

  5. 1..2..3..
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The code has a compile-time error. The main method is missing its closing brace - line 8 starts the try block but the main method never closes before the run method is declared. This makes the code structurally invalid and it will not compile.