E-Commerce Development Mobile Commerce 3 — Questions and Answers
Question 1: Which mobile commerce metric measures the percentage of users who add an item to the cart but never complete purchase?
- Cart abandonment rate (Correct answer)
- Bounce rate
- Exit rate
- Conversion funnel drop
Correct answer: Cart abandonment rate
Cart abandonment rate = (sessions with add-to-cart but no purchase) / (sessions with add-to-cart), expressed as a percentage.
Question 2: What does the viewport meta tag `<meta name='viewport' content='width=device-width, initial-scale=1'>` accomplish?
- Makes the page width match the device's physical screen width at 1:1 zoom (Correct answer)
- Forces landscape orientation
- Disables browser zoom entirely
- Sets the pixel density to 1x only
Correct answer: Makes the page width match the device's physical screen width at 1:1 zoom
This tag prevents mobile browsers from scaling the page down by mapping CSS pixels to device-width at scale 1.
Question 3: Apple Pay and Google Pay use which underlying protocol to transmit encrypted payment tokens to merchants?
- Tokenization via payment networks (EMVCo) (Correct answer)
- SSL mutual TLS only
- OAuth JWT tokens
- ISO 8583 bitmap
Correct answer: Tokenization via payment networks (EMVCo)
Both wallets use EMVCo-standard tokenization, replacing real card numbers with network-specific tokens that are useless if intercepted.
Question 4: A Lighthouse mobile audit reports a Total Blocking Time (TBT) of 350ms. What is the likely cause?
- Long JavaScript tasks blocking the main thread (Correct answer)
- Images above 200KB
- Missing ARIA labels
- Slow server response time (TTFB)
Correct answer: Long JavaScript tasks blocking the main thread
TBT measures time the main thread is blocked by long tasks (>50ms), almost always caused by heavy JavaScript execution.
Question 5: In a React Native mobile commerce app, which component should be used instead of a standard <ScrollView> to efficiently render large product lists?
- FlatList (Correct answer)
- ListView
- VirtualScroll
- InfiniteList
Correct answer: FlatList
FlatList uses windowing to render only visible items, preventing memory overflow on large datasets.
Question 6: What is 'deep linking' in the context of a mobile commerce app?
- A URL that opens a specific screen inside a native app (Correct answer)
- A link that bypasses CDN caching
- An HTTP/2 server push preload
- A hyperlink pointing to database records
Correct answer: A URL that opens a specific screen inside a native app
Deep links use custom URI schemes or Universal Links/App Links to navigate users directly to a specific in-app screen from emails, ads, or web pages.
Question 7: Which HTTP header should a mobile e-commerce server send to enable HTTPS-only access and prevent protocol downgrade attacks?
- Strict-Transport-Security (Correct answer)
- Content-Security-Policy
- X-Frame-Options
- Cache-Control: no-store
Correct answer: Strict-Transport-Security
HSTS (Strict-Transport-Security) instructs browsers to always connect via HTTPS for the specified max-age duration.
E-Commerce Development Mobile Commerce 3
Which mobile commerce metric measures the percentage of users who add an item to the cart but never complete purchase?