Mobile Applications ISE Practice Questions (Page 5)

Questions 21–25

1. 21application · medium

   A city deploys a network of public environmental sensors (air quality, noise, temperature) and provides a mobile app for residents. The app must be usable by people with visual impairments and by users with low-end Android devices on slow networks. Which design choice best addresses both accessibility and usability constraints?

   • AUse a rich graphical dashboard with animated charts and require a fast connection for all features
   • BRely solely on voice commands and do not provide any visual interface
   • CProvide high-contrast text, support screen readers, and offer a lightweight 'text-only' mode that fetches only essential data
   • DMake the app require the latest smartphone model to ensure performance
   Reveal Solution Discussion Select an answer first
2. 22expert · hard

   A company is developing a mobile app to control a fleet of electric vehicle charging stations. The stations support both MQTT and CoAP for control messages. The app must work reliably over cellular networks with high latency and occasional packet loss. The development team is debating whether to use MQTT or CoAP for the control channel. Which protocol choice is more appropriate for this scenario, and why?

   • AMQTT, because it provides reliable message delivery with QoS levels and persistent sessions that handle intermittent connectivity
   • BCoAP, because it uses a request/response model that is easier for mobile apps to implement
   • CMQTT, because it is always faster than CoAP on high-latency networks
   • DCoAP, because it is UDP-based and therefore inherently more reliable than TCP
   Reveal Solution Discussion Select an answer first
4. 23expert · hard

   A smart home company is designing a mobile app to control a security camera. The camera supports both local streaming over Wi-Fi and remote streaming through a cloud relay. The security team requires that video streams be encrypted and that only the authenticated homeowner can view them. The product team wants the lowest possible latency for local viewing. Which design best satisfies both security and latency requirements?

   • AUse a VPN tunnel from the phone to the camera for both local and remote streaming
   • BUse a local TLS/DTLS session for LAN streaming and a cloud relay with TLS for remote streaming
   • CAlways stream through the cloud relay with TLS, even when the phone is on the same LAN
   • DUse unencrypted local streaming for low latency and rely on the home network's firewall for security
   Reveal Solution Discussion Select an answer first
5. 24application · medium

   A home automation company is designing a mobile app for controlling smart lights, thermostats, and door locks. The user base includes elderly individuals and people with visual impairments. The app must be usable by people with limited dexterity and those who rely on screen readers. Which design approach best addresses the accessibility and usability requirements for this diverse user base?

   • ARequire users to perform complex multi-step gestures to control devices and provide no alternative input methods.
   • BImplement large touch targets, high-contrast themes, and full support for the platform's screen reader (e.g., VoiceOver or TalkBack).
   • CUse small, densely packed controls to display more information on a single screen and rely on color alone to convey status.
   • DProvide a text-only interface with no graphical elements to simplify the user experience.
   Reveal Solution Discussion Select an answer first
6. 25expert · hard

   A company is developing a mobile app for controlling smart locks in a residential building. The app must support both local control (when the user is near the lock) and remote control (when the user is away). The company wants to minimize the attack surface and ensure that local control works even if the cloud is unavailable. Which architecture best meets these requirements?

   • AThe app uses a peer-to-peer mesh network to communicate with the lock and other devices, bypassing the cloud entirely.
   • BThe app communicates directly with the lock via Bluetooth for local control and with the cloud for remote control.
   • CThe app communicates with a local gateway that is always connected to the cloud.
   • DThe app communicates only with the cloud, which relays commands to the lock.
   Reveal Solution Discussion Select an answer first