A vector is multiplied by positive number then:

Explanation

The correct option is (a) - when a vector is multiplied by a positive number, its magnitude changes. Let's go through each option and explain them: (a) Its magnitude changes: When a vector is multiplied by a positive number, the resulting vector will have a different magnitude. The magnitude of a vector represents its length or size, and scaling it by a positive factor will change its magnitude. (b) Its direction changes but magnitude remains the same: If a vector's direction changes, it means it is pointing in a different direction. So, this option is not correct. When a vector is multiplied by a positive number, its direction may or may not change, but its magnitude will definitely change. (c) Its magnitude as well as direction changes: While the direction of a vector may change when multiplied by a positive number, it is not always the case. The magnitude will definitely change, but the direction may or may not change depending on the specific vector and the positive number used for scaling. (d) Neither its magnitude nor direction changes: This option is not correct. When a vector is multiplied by a positive number, at least its magnitude will change, and in some cases, the direction may also change. In summary, when a vector is multiplied by a positive number, its magnitude will change.