JavaScript Values Mocktest

The value 42 represents a numeric value in JavaScript. Numeric values can be integers or floating-point numbers, and they are used for mathematical calculations and numerical data. Options A, B, and D represent a string, Boolean, and array respectively, which are not numeric values. Therefore, option C is correct for representing a numeric value.

In JavaScript, when a string that represents a number is used with the - operator, it is converted to a number and the subtraction is performed. Therefore, the value of the expression "20" - 10 is 10. Option A is correct for the value of the expression.

The value [1, 2, 3] represents an array in JavaScript. Arrays are used to store multiple values in a single variable, and they are defined using square brackets []. Options A, B, and D represent an object, string, and Boolean respectively, which are not arrays. Therefore, option C is correct for representing an array.

In JavaScript, when a number is multiplied by a string that represents a number, the string is converted to a number and the multiplication is performed. Therefore, the result of the expression 5 * "3" is 15. Option A is correct for the result of the expression.

The logical AND operator (&&) in JavaScript returns true if both operands are true; otherwise, it returns false. Therefore, the value of the expression true && false is false. Option B is correct for the value of the expression.

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The value {name: 'Alice', age: 30} represents an object in JavaScript. Objects are used to store collections of key-value pairs, and they are defined using curly braces {}. Options A, B, and D represent an array, number, and Boolean respectively, which are not objects. Therefore, option C is correct for representing an object.

The logical NOT operator (!) in JavaScript negates the value of its operand. Therefore, the value of the expression !(5 > 3) (which is equivalent to 5 <= 3) is false because the condition (5 > 3) is true. Option B is correct for the value of the expression.

In JavaScript, when a string is concatenated with a number using the + operator, the number is converted to a string and concatenated with the string. Therefore, the result of the expression "10" + 5 is "105". Option A is correct for the result of the expression.

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